diff --git a/bypy/init_env.py b/bypy/init_env.py
index a16e06ab2f..3da499f1d1 100644
--- a/bypy/init_env.py
+++ b/bypy/init_env.py
@@ -8,10 +8,8 @@ import re
 import subprocess
 import sys
 
-from bypy.constants import (
-    LIBDIR, PREFIX, PYTHON, SRC as CALIBRE_DIR, build_dir, islinux, ismacos,
-    worker_env
-)
+from bypy.constants import LIBDIR, PREFIX, PYTHON, build_dir, islinux, ismacos, worker_env
+from bypy.constants import SRC as CALIBRE_DIR
 from bypy.utils import run_shell
 
 dlls = [
diff --git a/bypy/linux/__main__.py b/bypy/linux/__main__.py
index ebdfe96644..acff193a92 100644
--- a/bypy/linux/__main__.py
+++ b/bypy/linux/__main__.py
@@ -12,16 +12,10 @@ import tarfile
 import time
 from functools import partial
 
-from bypy.constants import (
-    LIBDIR, OUTPUT_DIR, PREFIX, SRC as CALIBRE_DIR, python_major_minor_version,
-)
-from bypy.freeze import (
-    extract_extension_modules, fix_pycryptodome, freeze_python, is_package_dir,
-    path_to_freeze_dir,
-)
-from bypy.utils import (
-    create_job, get_dll_path, mkdtemp, parallel_build, py_compile, run, walk,
-)
+from bypy.constants import LIBDIR, OUTPUT_DIR, PREFIX, python_major_minor_version
+from bypy.constants import SRC as CALIBRE_DIR
+from bypy.freeze import extract_extension_modules, fix_pycryptodome, freeze_python, is_package_dir, path_to_freeze_dir
+from bypy.utils import create_job, get_dll_path, mkdtemp, parallel_build, py_compile, run, walk
 
 j = os.path.join
 self_dir = os.path.dirname(os.path.abspath(__file__))
diff --git a/bypy/macos/__main__.py b/bypy/macos/__main__.py
index f0f9d43a93..bc6f423e11 100644
--- a/bypy/macos/__main__.py
+++ b/bypy/macos/__main__.py
@@ -19,16 +19,10 @@ import zipfile
 from functools import partial, reduce
 from itertools import repeat
 
-from bypy.constants import (
-    OUTPUT_DIR, PREFIX, PYTHON, SRC as CALIBRE_DIR, python_major_minor_version,
-)
-from bypy.freeze import (
-    extract_extension_modules, fix_pycryptodome, freeze_python, is_package_dir,
-    path_to_freeze_dir,
-)
-from bypy.utils import (
-    current_dir, get_arches_in_binary, mkdtemp, py_compile, timeit, walk,
-)
+from bypy.constants import OUTPUT_DIR, PREFIX, PYTHON, python_major_minor_version
+from bypy.constants import SRC as CALIBRE_DIR
+from bypy.freeze import extract_extension_modules, fix_pycryptodome, freeze_python, is_package_dir, path_to_freeze_dir
+from bypy.utils import current_dir, get_arches_in_binary, mkdtemp, py_compile, timeit, walk
 
 abspath, join, basename, dirname = os.path.abspath, os.path.join, os.path.basename, os.path.dirname
 iv = globals()['init_env']
diff --git a/bypy/macos/sign.py b/bypy/macos/sign.py
index 3279255aa7..c2ba8efbfd 100644
--- a/bypy/macos/sign.py
+++ b/bypy/macos/sign.py
@@ -6,10 +6,7 @@ import os
 import plistlib
 from glob import glob
 
-from bypy.macos_sign import (
-    codesign, create_entitlements_file, make_certificate_useable, notarize_app,
-    verify_signature
-)
+from bypy.macos_sign import codesign, create_entitlements_file, make_certificate_useable, notarize_app, verify_signature
 from bypy.utils import current_dir
 
 entitlements = {
diff --git a/bypy/macos/site.py b/bypy/macos/site.py
index 90545770e9..26c3d18c5e 100644
--- a/bypy/macos/site.py
+++ b/bypy/macos/site.py
@@ -1,6 +1,7 @@
 import builtins
 import os
 import sys
+
 import _sitebuiltins
 
 USER_SITE = None
diff --git a/bypy/windows/__main__.py b/bypy/windows/__main__.py
index ba6aaad858..d9eb08c0fd 100644
--- a/bypy/windows/__main__.py
+++ b/bypy/windows/__main__.py
@@ -15,14 +15,9 @@ import subprocess
 import sys
 import zipfile
 
-from bypy.constants import (
-    CL, LINK, MT, PREFIX, RC, SIGNTOOL, SRC as CALIBRE_DIR, SW, build_dir,
-    python_major_minor_version, worker_env
-)
-from bypy.freeze import (
-    cleanup_site_packages, extract_extension_modules, freeze_python,
-    path_to_freeze_dir
-)
+from bypy.constants import CL, LINK, MT, PREFIX, RC, SIGNTOOL, SW, build_dir, python_major_minor_version, worker_env
+from bypy.constants import SRC as CALIBRE_DIR
+from bypy.freeze import cleanup_site_packages, extract_extension_modules, freeze_python, path_to_freeze_dir
 from bypy.utils import mkdtemp, py_compile, run, walk
 
 iv = globals()['init_env']
diff --git a/bypy/windows/site.py b/bypy/windows/site.py
index 1563c330f2..2871855025 100644
--- a/bypy/windows/site.py
+++ b/bypy/windows/site.py
@@ -6,8 +6,8 @@ import builtins
 import os
 import sys
 from importlib import import_module
-from importlib.util import spec_from_file_location
 from importlib.machinery import EXTENSION_SUFFIXES
+from importlib.util import spec_from_file_location
 
 import _sitebuiltins
 
@@ -96,6 +96,7 @@ if __name__ == '__main__':
     except Exception:
         if sys.gui_app and sys.excepthook == sys.__excepthook__:
             import traceback
+
             import calibre_os_module
             calibre_os_module.gui_error_message(
                 f"Unhandled exception running {sys.calibre_basename}",
diff --git a/bypy/windows/wix.py b/bypy/windows/wix.py
index b404bed6d9..5c93e21c4b 100644
--- a/bypy/windows/wix.py
+++ b/bypy/windows/wix.py
@@ -2,9 +2,9 @@
 # vim:fileencoding=utf-8
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
-from itertools import count
 import os
 import shutil
+from itertools import count
 
 from bypy.constants import is64bit
 from bypy.utils import run
diff --git a/icons/icns/make_iconsets.py b/icons/icns/make_iconsets.py
index b81705865e..c9bf6f88dc 100644
--- a/icons/icns/make_iconsets.py
+++ b/icons/icns/make_iconsets.py
@@ -5,7 +5,10 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, shutil, subprocess, sys
+import os
+import shutil
+import subprocess
+import sys
 
 d, j, a = (getattr(os.path, x) for x in ('dirname', 'join', 'abspath'))
 base = d(a(__file__))
diff --git a/icons/make_ico_files.py b/icons/make_ico_files.py
index 23378e7d6f..179d7606db 100644
--- a/icons/make_ico_files.py
+++ b/icons/make_ico_files.py
@@ -5,7 +5,10 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, shutil, subprocess, sys
+import os
+import shutil
+import subprocess
+import sys
 
 d, j, a = (getattr(os.path, x) for x in ('dirname', 'join', 'abspath'))
 base = d(a(__file__))
diff --git a/imgsrc/generate.py b/imgsrc/generate.py
index c0d41a639d..9adaeab79f 100755
--- a/imgsrc/generate.py
+++ b/imgsrc/generate.py
@@ -2,7 +2,12 @@
 # vim:fileencoding=utf-8
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
-import os, glob, subprocess, argparse, json, hashlib
+import argparse
+import glob
+import hashlib
+import json
+import os
+import subprocess
 
 duplicates = {
     'character-set': ['languages'],
diff --git a/imgsrc/render-logo.py b/imgsrc/render-logo.py
index 806aa6cf5e..82d85072ae 100755
--- a/imgsrc/render-logo.py
+++ b/imgsrc/render-logo.py
@@ -3,7 +3,10 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import os, subprocess, sys, shutil
+import os
+import shutil
+import subprocess
+import sys
 
 j = os.path.join
 base = os.path.dirname(os.path.abspath(__file__))
diff --git a/imgsrc/srv/generate.py b/imgsrc/srv/generate.py
index bc043fb432..c56f3140f6 100644
--- a/imgsrc/srv/generate.py
+++ b/imgsrc/srv/generate.py
@@ -3,7 +3,9 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import os, re, sys
+import os
+import re
+import sys
 
 from lxml import etree
 
diff --git a/manual/build.py b/manual/build.py
index 4027691e11..0fdfb90d3a 100755
--- a/manual/build.py
+++ b/manual/build.py
@@ -5,7 +5,10 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import sys, os, subprocess, shutil
+import os
+import shutil
+import subprocess
+import sys
 import tempfile
 from functools import partial
 
@@ -14,8 +17,10 @@ BASE = d(a(__file__))
 SPHINX_BUILD = ['sphinx-build']
 
 sys.path.insert(0, d(BASE))
-from setup import __appname__, __version__
 from calibre.ebooks.oeb.polish.container import epub_to_azw3
+
+from setup import __appname__, __version__
+
 sys.path.remove(d(BASE))
 
 
diff --git a/manual/conf.py b/manual/conf.py
index 26cb887d8b..966de55a2e 100644
--- a/manual/conf.py
+++ b/manual/conf.py
@@ -11,17 +11,21 @@
 # All configuration values have a default value; values that are commented out
 # serve to show the default value.
 
-import sys, os, errno
+import errno
+import os
+import sys
 from datetime import date
 
 # If your extensions are in another directory, add it here.
 base = os.path.dirname(os.path.abspath(__file__))
 sys.path.append(base)
 sys.path.insert(0, os.path.dirname(base))
-from setup import __appname__, __version__
-from calibre.utils.localization import localize_website_link
 import calibre.utils.img as cimg
 import custom
+from calibre.utils.localization import localize_website_link
+
+from setup import __appname__, __version__
+
 del sys.path[0]
 custom, cimg
 # General configuration
@@ -158,6 +162,7 @@ html_last_updated_fmt = '%b %d, %Y'
 html_short_title = _('Start')
 
 from calibre.utils.localization import get_language
+
 html_context = {}
 html_context['other_languages'] = [
     (lc, get_language(lc)) for lc in os.environ.get('ALL_USER_MANUAL_LANGUAGES', '').split() if lc != language]
diff --git a/manual/custom.py b/manual/custom.py
index 3b280593d5..aaec02e502 100644
--- a/manual/custom.py
+++ b/manual/custom.py
@@ -6,11 +6,10 @@ import os
 import re
 from functools import partial
 
-from sphinx.util.console import bold
-from sphinx.util.logging import getLogger
-
 from calibre.linux import cli_index_strings, entry_points
 from epub import EPUBHelpBuilder
+from sphinx.util.console import bold
+from sphinx.util.logging import getLogger
 
 
 def info(*a):
@@ -86,7 +85,7 @@ def titlecase(language, x):
 
 
 def generate_calibredb_help(preamble, language):
-    from calibre.db.cli.main import COMMANDS, option_parser_for, get_parser
+    from calibre.db.cli.main import COMMANDS, get_parser, option_parser_for
     preamble = preamble[:preamble.find('\n\n\n', preamble.find('code-block'))]
     preamble += '\n\n'
     preamble += _('''\
@@ -156,8 +155,8 @@ details and examples.
 
 
 def generate_ebook_convert_help(preamble, app):
-    from calibre.ebooks.conversion.cli import create_option_parser, manual_index_strings
     from calibre.customize.ui import input_format_plugins, output_format_plugins
+    from calibre.ebooks.conversion.cli import create_option_parser, manual_index_strings
     from calibre.utils.logging import default_log
     preamble = re.sub(r'http.*\.html', ':ref:`conversion`', preamble)
 
diff --git a/manual/epub.py b/manual/epub.py
index 8a6ca38e2e..c3cf010f3d 100644
--- a/manual/epub.py
+++ b/manual/epub.py
@@ -8,13 +8,13 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from sphinx.builders.epub3 import Epub3Builder as EpubBuilder
-
 from calibre.ebooks.oeb.base import OPF
-from calibre.ebooks.oeb.polish.container import get_container, OEB_DOCS
-from calibre.ebooks.oeb.polish.check.links import check_links, UnreferencedResource
+from calibre.ebooks.oeb.polish.check.links import UnreferencedResource, check_links
+from calibre.ebooks.oeb.polish.container import OEB_DOCS, get_container
 from calibre.ebooks.oeb.polish.pretty import pretty_html_tree, pretty_opf
 from calibre.utils.imghdr import identify
+from sphinx.builders.epub3 import Epub3Builder as EpubBuilder
+
 from polyglot.builtins import iteritems
 
 
diff --git a/manual/plugin_examples/editor_demo/main.py b/manual/plugin_examples/editor_demo/main.py
index 33cbf501ba..1262c8720e 100644
--- a/manual/plugin_examples/editor_demo/main.py
+++ b/manual/plugin_examples/editor_demo/main.py
@@ -6,15 +6,15 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
-from qt.core import QAction, QInputDialog
-from css_parser.css import CSSRule
+
+from calibre import force_unicode
+from calibre.ebooks.oeb.polish.container import OEB_DOCS, OEB_STYLES, serialize
+from calibre.gui2 import error_dialog
 
 # The base class that all tools must inherit from
 from calibre.gui2.tweak_book.plugin import Tool
-
-from calibre import force_unicode
-from calibre.gui2 import error_dialog
-from calibre.ebooks.oeb.polish.container import OEB_DOCS, OEB_STYLES, serialize
+from css_parser.css import CSSRule
+from qt.core import QAction, QInputDialog
 
 
 class DemoTool(Tool):
diff --git a/manual/plugin_examples/helloworld/__init__.py b/manual/plugin_examples/helloworld/__init__.py
index f8fde737c3..60b3cb570b 100644
--- a/manual/plugin_examples/helloworld/__init__.py
+++ b/manual/plugin_examples/helloworld/__init__.py
@@ -7,8 +7,10 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import os
+
 from calibre.customize import FileTypePlugin
 
+
 class HelloWorld(FileTypePlugin):
 
     name                = 'Hello World Plugin' # Name of the plugin
diff --git a/manual/plugin_examples/interface_demo/__init__.py b/manual/plugin_examples/interface_demo/__init__.py
index 1aa5d4fbf2..f6733549f2 100644
--- a/manual/plugin_examples/interface_demo/__init__.py
+++ b/manual/plugin_examples/interface_demo/__init__.py
@@ -9,6 +9,7 @@ __docformat__ = 'restructuredtext en'
 # The class that all Interface Action plugin wrappers must inherit from
 from calibre.customize import InterfaceActionBase
 
+
 class InterfacePluginDemo(InterfaceActionBase):
     '''
     This class is a simple wrapper that provides information about the actual
diff --git a/manual/plugin_examples/interface_demo/config.py b/manual/plugin_examples/interface_demo/config.py
index 00319b0e22..0dd8c8a473 100644
--- a/manual/plugin_examples/interface_demo/config.py
+++ b/manual/plugin_examples/interface_demo/config.py
@@ -6,9 +6,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import QWidget, QHBoxLayout, QLabel, QLineEdit
-
 from calibre.utils.config import JSONConfig
+from qt.core import QHBoxLayout, QLabel, QLineEdit, QWidget
 
 # This is where all preferences for this plugin will be stored
 # Remember that this name (i.e. plugins/interface_demo) is also
diff --git a/manual/plugin_examples/interface_demo/main.py b/manual/plugin_examples/interface_demo/main.py
index d9417b3a87..a8dd3e658e 100644
--- a/manual/plugin_examples/interface_demo/main.py
+++ b/manual/plugin_examples/interface_demo/main.py
@@ -12,9 +12,8 @@ if False:
     # You do not need this code in your plugins
     get_icons = get_resources = None
 
-from qt.core import QDialog, QVBoxLayout, QPushButton, QMessageBox, QLabel
-
 from calibre_plugins.interface_demo.config import prefs
+from qt.core import QDialog, QLabel, QMessageBox, QPushButton, QVBoxLayout
 
 
 class DemoDialog(QDialog):
diff --git a/manual/sidebar_toc.py b/manual/sidebar_toc.py
index a2c4151239..b399c130b3 100644
--- a/manual/sidebar_toc.py
+++ b/manual/sidebar_toc.py
@@ -1,8 +1,9 @@
 #!/usr/bin/env python
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
 
-from docutils import nodes
 from itertools import count
+
+from docutils import nodes
 from sphinx.environment.adapters.toctree import TocTree
 
 id_counter = count()
diff --git a/setup.py b/setup.py
index 59533e6d68..5a250024b6 100755
--- a/setup.py
+++ b/setup.py
@@ -6,7 +6,10 @@ __license__ = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, re
+import os
+import re
+import sys
+
 src_base = os.path.dirname(os.path.abspath(__file__))
 
 
@@ -32,7 +35,7 @@ check_version_info()
 sys.path.insert(0, src_base)
 
 import setup.commands as commands
-from setup import prints, get_warnings
+from setup import get_warnings, prints
 
 
 def option_parser():
diff --git a/setup/__init__.py b/setup/__init__.py
index 8288fb8863..3553fb2dd1 100644
--- a/setup/__init__.py
+++ b/setup/__init__.py
@@ -6,6 +6,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import errno
+import hashlib
 import os
 import re
 import shutil
@@ -13,7 +14,6 @@ import subprocess
 import sys
 import tempfile
 import time
-import hashlib
 from contextlib import contextmanager
 from functools import lru_cache
 
@@ -167,7 +167,7 @@ def get_warnings():
 
 def edit_file(path):
     return subprocess.Popen([
-        'vim', '-c', 'ALELint', '-c', 'ALEFirst', '-S', os.path.join(SRC, '../session.vim'), '-f', path
+        os.environ.get('EDITOR', 'vim'), '-S', os.path.join(SRC, '../session.vim'), '-f', path
     ]).wait() == 0
 
 
diff --git a/setup/browser_data.py b/setup/browser_data.py
index 33f9a0294b..c2583078b3 100644
--- a/setup/browser_data.py
+++ b/setup/browser_data.py
@@ -4,8 +4,8 @@
 
 import bz2
 import os
-import sys
 import ssl
+import sys
 from datetime import datetime, timezone
 from urllib.request import urlopen
 
diff --git a/setup/build.py b/setup/build.py
index 9e46f565e9..d0a6891902 100644
--- a/setup/build.py
+++ b/setup/build.py
@@ -15,7 +15,7 @@ import sys
 import sysconfig
 import textwrap
 from functools import partial
-from typing import NamedTuple, List
+from typing import List, NamedTuple
 
 from setup import SRC, Command, isbsd, isfreebsd, ishaiku, islinux, ismacos, iswindows
 
diff --git a/setup/check.py b/setup/check.py
index 352a8d5bfd..afe85be24e 100644
--- a/setup/check.py
+++ b/setup/check.py
@@ -5,8 +5,13 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, json, subprocess, errno, hashlib
-from setup import Command, build_cache_dir, edit_file, dump_json
+import errno
+import hashlib
+import json
+import os
+import subprocess
+
+from setup import Command, build_cache_dir, dump_json, edit_file
 
 
 class Message:
diff --git a/setup/commands.py b/setup/commands.py
index 64b06a5d42..266b4a1dcc 100644
--- a/setup/commands.py
+++ b/setup/commands.py
@@ -23,7 +23,8 @@ __all__ = [
     'export_packages', 'hyphenation', 'liberation_fonts', 'stylelint', 'xwin',
 ]
 
-from setup.installers import Linux, Win, OSX, Linux64, LinuxArm64, Win64, ExtDev, BuildDep, ExportPackages
+from setup.installers import OSX, BuildDep, ExportPackages, ExtDev, Linux, Linux64, LinuxArm64, Win, Win64
+
 linux, linux64, linuxarm64 = Linux(), Linux64(), LinuxArm64()
 win, win64 = Win(), Win64()
 osx = OSX()
@@ -31,7 +32,8 @@ extdev = ExtDev()
 build_dep = BuildDep()
 export_packages = ExportPackages()
 
-from setup.translations import POT, GetTranslations, Translations, ISO639, ISO3166
+from setup.translations import ISO639, ISO3166, POT, GetTranslations, Translations
+
 pot = POT()
 translations = Translations()
 get_translations = GetTranslations()
@@ -39,49 +41,60 @@ iso639 = ISO639()
 iso3166 = ISO3166()
 
 from setup.csslint import CSSLint
+
 stylelint = CSSLint()
 
 from setup.build import Build
+
 build = Build()
 
 from setup.mathjax import MathJax
+
 mathjax = MathJax()
 
 from setup.hyphenation import Hyphenation
+
 hyphenation = Hyphenation()
 
 from setup.liberation import LiberationFonts
+
 liberation_fonts = LiberationFonts()
 
 from setup.git_version import GitVersion
+
 git_version = GitVersion()
 
-from setup.install import Develop, Install, Sdist, Bootstrap
+from setup.install import Bootstrap, Develop, Install, Sdist
+
 develop = Develop()
 install = Install()
 sdist = Sdist()
 bootstrap = Bootstrap()
 
 from setup.gui import GUI
+
 gui = GUI()
 
 from setup.check import Check, UpgradeSourceCode
+
 check = Check()
 upgrade_source_code = UpgradeSourceCode()
 
 from setup.test import Test, TestRS
+
 test = Test()
 test_rs = TestRS()
 
-from setup.resources import Resources, Kakasi, CACerts, RapydScript, RecentUAs
+from setup.resources import CACerts, Kakasi, RapydScript, RecentUAs, Resources
+
 resources = Resources()
 kakasi = Kakasi()
 cacerts = CACerts()
 recent_uas = RecentUAs()
 rapydscript = RapydScript()
 
-from setup.publish import Manual, TagRelease, Stage1, Stage2, \
-        Stage3, Stage4, Stage5, Publish, PublishBetas, PublishPreview, ManPages
+from setup.publish import ManPages, Manual, Publish, PublishBetas, PublishPreview, Stage1, Stage2, Stage3, Stage4, Stage5, TagRelease
+
 manual = Manual()
 tag_release = TagRelease()
 stage1 = Stage1()
@@ -94,8 +107,8 @@ publish_betas = PublishBetas()
 publish_preview = PublishPreview()
 man_pages = ManPages()
 
-from setup.upload import (UploadUserManual, UploadDemo, UploadInstallers,
-        UploadToServer, ReUpload)
+from setup.upload import ReUpload, UploadDemo, UploadInstallers, UploadToServer, UploadUserManual
+
 upload_user_manual = UploadUserManual()
 upload_demo = UploadDemo()
 upload_to_server = UploadToServer()
@@ -104,6 +117,7 @@ reupload = ReUpload()
 
 
 from setup.xwin import XWin
+
 xwin = XWin()
 
 commands = {}
diff --git a/setup/file-hosting-bw.py b/setup/file-hosting-bw.py
index f2ad65c342..c179e6fb4a 100644
--- a/setup/file-hosting-bw.py
+++ b/setup/file-hosting-bw.py
@@ -4,7 +4,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, subprocess, socket
+import os
+import socket
+import subprocess
 
 BASE = '/srv/download/bw'
 
diff --git a/setup/git_post_checkout_hook.py b/setup/git_post_checkout_hook.py
index 71546b437b..3d244a0af2 100755
--- a/setup/git_post_checkout_hook.py
+++ b/setup/git_post_checkout_hook.py
@@ -3,7 +3,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, subprocess, sys
+import os
+import subprocess
+import sys
 
 prev_rev, current_rev, flags = sys.argv[1:]
 
diff --git a/setup/git_post_rewrite_hook.py b/setup/git_post_rewrite_hook.py
index 79474bde86..bc5c450487 100755
--- a/setup/git_post_rewrite_hook.py
+++ b/setup/git_post_rewrite_hook.py
@@ -3,7 +3,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import subprocess, os, sys
+import os
+import subprocess
+import sys
 
 base = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
 os.chdir(base)
diff --git a/setup/git_pre_commit_hook.py b/setup/git_pre_commit_hook.py
index 21d3d0996d..90fb181d04 100755
--- a/setup/git_pre_commit_hook.py
+++ b/setup/git_pre_commit_hook.py
@@ -11,6 +11,7 @@ import sys
 import urllib.error
 import urllib.parse
 import urllib.request
+
 from lxml import html
 
 '''
diff --git a/setup/hosting.py b/setup/hosting.py
index 2c367f9780..b0dc825aa2 100644
--- a/setup/hosting.py
+++ b/setup/hosting.py
@@ -4,11 +4,16 @@ __license__ = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, time, sys, shutil, json, mimetypes
-from pprint import pprint
+import json
+import mimetypes
+import os
+import shutil
+import sys
+import time
 from argparse import ArgumentParser, FileType
-from subprocess import check_call
 from collections import OrderedDict
+from pprint import pprint
+from subprocess import check_call
 
 
 class ReadFileWithProgressReporting:  # {{{
diff --git a/setup/install.py b/setup/install.py
index 3691565309..a9c3a40430 100644
--- a/setup/install.py
+++ b/setup/install.py
@@ -12,10 +12,7 @@ import tempfile
 import textwrap
 import time
 
-from setup import (
-    Command, __appname__, __version__, basenames, functions,
-    isbsd, ishaiku, islinux, modules
-)
+from setup import Command, __appname__, __version__, basenames, functions, isbsd, ishaiku, islinux, modules
 
 HEADER = '''\
 #!/usr/bin/env python{py_major_version}
diff --git a/setup/installers.py b/setup/installers.py
index ef55612552..2a2de8809d 100644
--- a/setup/installers.py
+++ b/setup/installers.py
@@ -2,11 +2,14 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import os, sys, subprocess, binascii, json
+import binascii
+import json
+import os
+import subprocess
+import sys
 
 from setup import Command
 
-
 d = os.path.dirname
 
 
diff --git a/setup/iso_codes.py b/setup/iso_codes.py
index 3a3bfecd12..66d196357f 100644
--- a/setup/iso_codes.py
+++ b/setup/iso_codes.py
@@ -3,7 +3,8 @@
 
 import fnmatch
 import os
-import shutil, time
+import shutil
+import time
 import zipfile
 from io import BytesIO
 
diff --git a/setup/lc_data.py b/setup/lc_data.py
index f632db152c..4e252afcb1 100644
--- a/setup/lc_data.py
+++ b/setup/lc_data.py
@@ -8,7 +8,11 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 # To regenerate run:
 # sudo locale-gen -A && python3 lc_time.py
 
-import locale, os, pprint, sys
+import locale
+import os
+import pprint
+import sys
+
 
 def generate_data():
     def nl(code):
diff --git a/setup/linux-installer.py b/setup/linux-installer.py
index e4aace9120..8cfdce9861 100644
--- a/setup/linux-installer.py
+++ b/setup/linux-installer.py
@@ -37,17 +37,18 @@ if machine.startswith('arm') or machine.startswith('aarch64'):
 if py3:
     unicode = str
     raw_input = input
-    from urllib.parse import urlparse
-    from urllib.request import BaseHandler, build_opener, Request, urlopen, getproxies, addinfourl
     import http.client as httplib
+    from urllib.parse import urlparse
+    from urllib.request import BaseHandler, Request, addinfourl, build_opener, getproxies, urlopen
     def encode_for_subprocess(x):
         return x
 else:
-    from future_builtins import map
-    from urlparse import urlparse
-    from urllib import urlopen, getproxies, addinfourl
-    from urllib2 import BaseHandler, build_opener, Request
+    from urllib import addinfourl, getproxies, urlopen
+
     import httplib
+    from future_builtins import map
+    from urllib2 import BaseHandler, Request, build_opener
+    from urlparse import urlparse
 
     def encode_for_subprocess(x):
         if isinstance(x, unicode):
diff --git a/setup/mathjax.py b/setup/mathjax.py
index fa81f29181..cf23e7b330 100644
--- a/setup/mathjax.py
+++ b/setup/mathjax.py
@@ -5,10 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, json
+import json
+import os
 from hashlib import sha1
 
-
 from setup.revendor import ReVendor
 
 
diff --git a/setup/parallel_build.py b/setup/parallel_build.py
index 0208bbaefc..015fb2d5d5 100644
--- a/setup/parallel_build.py
+++ b/setup/parallel_build.py
@@ -4,14 +4,20 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import subprocess, os, itertools, json, sys, shlex
-from multiprocessing.pool import ThreadPool as Pool
+import itertools
+import json
+import os
+import shlex
+import subprocess
+import sys
 from collections import namedtuple
-from threading import Thread
-from functools import partial
 from contextlib import closing
+from functools import partial
+from multiprocessing.pool import ThreadPool as Pool
+from threading import Thread
+
+from polyglot.builtins import as_bytes, unicode_type
 
-from polyglot.builtins import unicode_type, as_bytes
 Job = namedtuple('Job', 'cmd human_text cwd')
 
 cpu_count = min(16, max(1, os.cpu_count()))
diff --git a/setup/plugins_mirror.py b/setup/plugins_mirror.py
index 537c9780bd..2c94378540 100644
--- a/setup/plugins_mirror.py
+++ b/setup/plugins_mirror.py
@@ -45,9 +45,9 @@ except ImportError:
 
 try:
     from urllib.error import URLError
-    from urllib.request import urlopen, Request, build_opener
+    from urllib.request import Request, build_opener, urlopen
 except Exception:
-    from urllib2 import urlopen, Request, build_opener, URLError
+    from urllib2 import Request, URLError, build_opener, urlopen
 # }}}
 
 USER_AGENT = 'calibre mirror'
diff --git a/setup/publish.py b/setup/publish.py
index 280642fa6d..eb83130243 100644
--- a/setup/publish.py
+++ b/setup/publish.py
@@ -5,10 +5,17 @@ __license__ = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, shutil, subprocess, tempfile, json, time, filecmp, sys
+import filecmp
+import json
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+import time
 
-from setup import Command, __version__, require_clean_git, require_git_master, installer_names
-from setup.parallel_build import parallel_build, create_job
+from setup import Command, __version__, installer_names, require_clean_git, require_git_master
+from setup.parallel_build import create_job, parallel_build
 
 
 class Stage1(Command):
diff --git a/setup/resources.py b/setup/resources.py
index def7997576..a88b511b24 100644
--- a/setup/resources.py
+++ b/setup/resources.py
@@ -5,11 +5,17 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, re, shutil, zipfile, glob, json, errno
+import errno
+import glob
+import json
+import os
+import re
+import shutil
+import zipfile
 from zlib import compress
 
-from setup import Command, basenames, __appname__, download_securely, dump_json
-from polyglot.builtins import codepoint_to_chr, itervalues, iteritems, only_unicode_recursive
+from polyglot.builtins import codepoint_to_chr, iteritems, itervalues, only_unicode_recursive
+from setup import Command, __appname__, basenames, download_securely, dump_json
 
 
 def get_opts_from_parser(parser):
@@ -180,7 +186,7 @@ class RapydScript(Command):  # {{{
                 help='Only compile the specified module')
 
     def run(self, opts):
-        from calibre.utils.rapydscript import compile_srv, compile_editor, compile_viewer
+        from calibre.utils.rapydscript import compile_editor, compile_srv, compile_viewer
         if opts.only_module:
             locals()['compile_' + opts.only_module]()
         else:
@@ -210,8 +216,7 @@ class Resources(Command):  # {{{
             with open(dest, 'wb') as f:
                 f.write(msgpack_dumps(scripts))
 
-        from calibre.web.feeds.recipes.collection import \
-                serialize_builtin_recipes, iterate_over_builtin_recipe_files
+        from calibre.web.feeds.recipes.collection import iterate_over_builtin_recipe_files, serialize_builtin_recipes
 
         files = [x[1] for x in iterate_over_builtin_recipe_files()]
 
@@ -270,6 +275,7 @@ class Resources(Command):  # {{{
         dest = self.j(self.RESOURCES, 'template-functions.json')
         function_dict = {}
         import inspect
+
         from calibre.utils.formatter_functions import formatter_functions
         for obj in formatter_functions().get_builtins().values():
             eval_func = inspect.getmembers(obj,
diff --git a/setup/run-calibre-worker.py b/setup/run-calibre-worker.py
index a048e2a9f4..6cbcc4e695 100644
--- a/setup/run-calibre-worker.py
+++ b/setup/run-calibre-worker.py
@@ -2,7 +2,9 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import sys, os
+import os
+import sys
+
 sys.setup_dir = os.path.dirname(os.path.abspath(__file__))
 SRC = os.path.abspath(os.path.join(os.path.dirname(sys.setup_dir), 'src'))
 sys.path.insert(0, SRC)
@@ -11,4 +13,5 @@ sys.extensions_location = os.path.join(SRC, 'calibre', 'plugins')
 sys.running_from_setup = True
 
 from calibre.utils.ipc.worker import main
+
 sys.exit(main())
diff --git a/setup/test.py b/setup/test.py
index 0a9fd14b2e..1a82e0d454 100644
--- a/setup/test.py
+++ b/setup/test.py
@@ -6,7 +6,8 @@ import os
 import subprocess
 import sys
 
-from setup import Command, ismacos, is_ci
+from setup import Command, is_ci, ismacos
+
 TEST_MODULES = frozenset('srv db polish opf css docx cfi matcher icu smartypants build misc dbcli ebooks'.split())
 
 
@@ -59,9 +60,7 @@ class Test(BaseTest):
             sys.libxslt_dylib = ctypes.CDLL(os.path.join(os.environ['SW'], 'lib', 'libxslt.dylib'))
             sys.libexslt_dylib = ctypes.CDLL(os.path.join(os.environ['SW'], 'lib', 'libexslt.dylib'))
             print(sys.libxml2_dylib, sys.libxslt_dylib, sys.libexslt_dylib, file=sys.stderr, flush=True)
-        from calibre.utils.run_tests import (
-            filter_tests_by_name, remove_tests_by_name, run_cli, find_tests
-        )
+        from calibre.utils.run_tests import filter_tests_by_name, find_tests, remove_tests_by_name, run_cli
         tests = find_tests(which_tests=frozenset(opts.test_module), exclude_tests=frozenset(opts.exclude_test_module))
         if opts.test_name:
             tests = filter_tests_by_name(tests, *opts.test_name)
diff --git a/setup/translations.py b/setup/translations.py
index fea29f69bf..168b3c87e3 100644
--- a/setup/translations.py
+++ b/setup/translations.py
@@ -5,15 +5,27 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, tempfile, shutil, subprocess, glob, re, time, textwrap, shlex, json, errno, hashlib, sys
+import errno
+import glob
+import hashlib
+import json
+import os
+import re
+import shlex
+import shutil
+import subprocess
+import sys
+import tempfile
+import textwrap
+import time
 from collections import defaultdict
-from locale import normalize as normalize_locale
 from functools import partial
+from locale import normalize as normalize_locale
 
-from setup import Command, __appname__, __version__, require_git_master, build_cache_dir, edit_file, dump_json, is_ci
-from setup.parallel_build import batched_parallel_jobs
-from setup.iso_codes import iso_data
 from polyglot.builtins import codepoint_to_chr, iteritems
+from setup import Command, __appname__, __version__, build_cache_dir, dump_json, edit_file, is_ci, require_git_master
+from setup.iso_codes import iso_data
+from setup.parallel_build import batched_parallel_jobs
 
 
 def qt_sources():
@@ -439,7 +451,7 @@ class Translations(POT):  # {{{
     def compile_content_server_translations(self):
         self.info('Compiling content-server translations')
         from calibre.utils.rapydscript import msgfmt
-        from calibre.utils.zipfile import ZipFile, ZIP_DEFLATED, ZipInfo, ZIP_STORED
+        from calibre.utils.zipfile import ZIP_DEFLATED, ZIP_STORED, ZipFile, ZipInfo
         with ZipFile(self.j(self.RESOURCES, 'content-server', 'locales.zip'), 'w', ZIP_DEFLATED) as zf:
             for src in glob.glob(os.path.join(self.TRANSLATIONS, 'content-server', '*.po')):
                 if not self.is_po_file_ok(src):
@@ -472,7 +484,7 @@ class Translations(POT):  # {{{
     def freeze_locales(self):
         zf = self.DEST + '.zip'
         from calibre import CurrentDir
-        from calibre.utils.zipfile import ZipFile, ZIP_DEFLATED
+        from calibre.utils.zipfile import ZIP_DEFLATED, ZipFile
         with ZipFile(zf, 'w', ZIP_DEFLATED) as zf:
             with CurrentDir(self.DEST):
                 zf.add_dir('.')
@@ -483,9 +495,9 @@ class Translations(POT):  # {{{
         return self.j(self.d(self.DEST), 'stats.calibre_msgpack')
 
     def _compile_website_translations(self, name='website', threshold=50):
-        from calibre.utils.zipfile import ZipFile, ZipInfo, ZIP_STORED
         from calibre.ptempfile import TemporaryDirectory
         from calibre.utils.localization import get_language, translator_for_lang
+        from calibre.utils.zipfile import ZIP_STORED, ZipFile, ZipInfo
         self.info('Compiling', name, 'translations...')
         srcbase = self.j(self.d(self.SRC), 'translations', name)
         if not os.path.exists(srcbase):
diff --git a/setup/upload.py b/setup/upload.py
index d1f48e58d5..7c0076d339 100644
--- a/setup/upload.py
+++ b/setup/upload.py
@@ -5,18 +5,27 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, subprocess, hashlib, shutil, glob, stat, sys, time, json
+import glob
+import hashlib
+import json
+import os
+import shutil
+import stat
+import subprocess
+import sys
+import time
 from subprocess import check_call
-from tempfile import NamedTemporaryFile, mkdtemp, gettempdir
+from tempfile import NamedTemporaryFile, gettempdir, mkdtemp
 from zipfile import ZipFile
+
 from polyglot.builtins import iteritems
-from polyglot.urllib import urlopen, Request
+from polyglot.urllib import Request, urlopen
 
 if __name__ == '__main__':
     d = os.path.dirname
     sys.path.insert(0, d(d(os.path.abspath(__file__))))
 
-from setup import Command, __version__, __appname__, installer_names
+from setup import Command, __appname__, __version__, installer_names
 
 DOWNLOADS = '/srv/main/downloads'
 HTML2LRF = "calibre/ebooks/lrf/html/demo"
diff --git a/setup/xwin.py b/setup/xwin.py
index b14219ea38..724eb28af6 100644
--- a/setup/xwin.py
+++ b/setup/xwin.py
@@ -2,7 +2,8 @@
 # License: GPLv3 Copyright: 2023, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import os, runpy
+import os
+import runpy
 import shutil
 
 from setup import Command
diff --git a/src/calibre/__init__.py b/src/calibre/__init__.py
index 4f0337573e..3d858548a6 100644
--- a/src/calibre/__init__.py
+++ b/src/calibre/__init__.py
@@ -3,10 +3,15 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, re, time, warnings
-from polyglot.builtins import codepoint_to_chr, hasenv, native_string_type
-from math import floor
+import os
+import re
+import sys
+import time
+import warnings
 from functools import partial
+from math import floor
+
+from polyglot.builtins import codepoint_to_chr, hasenv, native_string_type
 
 if not hasenv('CALIBRE_SHOW_DEPRECATION_WARNINGS'):
     warnings.simplefilter('ignore', DeprecationWarning)
@@ -15,13 +20,25 @@ try:
 except OSError:
     os.chdir(os.path.expanduser('~'))
 
-from calibre.constants import (iswindows, ismacos, islinux, isfrozen,
-        isbsd, preferred_encoding, __appname__, __version__, __author__,
-        plugins, filesystem_encoding, config_dir)
+from calibre.constants import (
+    __appname__,
+    __author__,
+    __version__,
+    config_dir,
+    filesystem_encoding,
+    isbsd,
+    isfrozen,
+    islinux,
+    ismacos,
+    iswindows,
+    plugins,
+    preferred_encoding,
+)
 from calibre.startup import initialize_calibre
+
 initialize_calibre()
-from calibre.utils.icu import safe_chr
 from calibre.prints import prints
+from calibre.utils.icu import safe_chr
 from calibre.utils.resources import get_path as P
 
 if False:
@@ -293,7 +310,7 @@ def is_mobile_ua(ua):
 
 
 def random_user_agent(choose=None, allow_ie=True):
-    from calibre.utils.random_ua import common_user_agents, choose_randomly_by_popularity
+    from calibre.utils.random_ua import choose_randomly_by_popularity, common_user_agents
     ua_list = common_user_agents()
     ua_list = tuple(x for x in ua_list if not is_mobile_ua(x))
     if not allow_ie:
diff --git a/src/calibre/build_forms.py b/src/calibre/build_forms.py
index d45992ec85..222aff76bd 100644
--- a/src/calibre/build_forms.py
+++ b/src/calibre/build_forms.py
@@ -1,8 +1,8 @@
 #!/usr/bin/env python
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
-import os
 import importlib
+import os
 
 
 def form_to_compiled_form(form):
@@ -39,6 +39,7 @@ def ensure_icons_built(resource_dir, force_compile, info):
 
 def build_forms(srcdir, info=None, summary=False, check_for_migration=False, check_icons=True):
     import re
+
     from qt.core import QT_VERSION_STR
     qt_major = QT_VERSION_STR.split('.')[0]
     m = importlib.import_module(f'PyQt{qt_major}.uic')
diff --git a/src/calibre/constants.py b/src/calibre/constants.py
index 51b5a6375d..4e2efe3455 100644
--- a/src/calibre/constants.py
+++ b/src/calibre/constants.py
@@ -1,8 +1,14 @@
 #!/usr/bin/env python
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
-from polyglot.builtins import environ_item, hasenv
+import codecs
+import collections
+import collections.abc
+import locale
+import os
+import sys
 from functools import lru_cache
-import sys, locale, codecs, os, collections, collections.abc
+
+from polyglot.builtins import environ_item, hasenv
 
 __appname__   = 'calibre'
 numeric_version = (7, 7, 101)
@@ -173,9 +179,9 @@ def cache_dir():
 plugins_loc = sys.extensions_location
 system_plugins_loc = getattr(sys, 'system_plugins_location', None)
 
-from importlib.machinery import ModuleSpec, EXTENSION_SUFFIXES, ExtensionFileLoader
-from importlib.util import find_spec
 from importlib import import_module
+from importlib.machinery import EXTENSION_SUFFIXES, ExtensionFileLoader, ModuleSpec
+from importlib.util import find_spec
 
 
 class DeVendorLoader:
@@ -389,7 +395,8 @@ else:
             not os.access(config_dir, os.W_OK) or not \
             os.access(config_dir, os.X_OK):
         print('No write access to', config_dir, 'using a temporary dir instead')
-        import tempfile, atexit
+        import atexit
+        import tempfile
         config_dir = tempfile.mkdtemp(prefix='calibre-config-')
 
         def cleanup_cdir():
diff --git a/src/calibre/customize/__init__.py b/src/calibre/customize/__init__.py
index 3bdf4a5f67..a50a76ac94 100644
--- a/src/calibre/customize/__init__.py
+++ b/src/calibre/customize/__init__.py
@@ -145,10 +145,7 @@ class Plugin:  # {{{
         True if the user clicks OK, False otherwise. The changes are
         automatically applied.
         '''
-        from qt.core import (
-            QApplication, QDialog, QDialogButtonBox, QLabel, QLineEdit, QScrollArea, Qt,
-            QVBoxLayout, QSize
-        )
+        from qt.core import QApplication, QDialog, QDialogButtonBox, QLabel, QLineEdit, QScrollArea, QSize, Qt, QVBoxLayout
 
         from calibre.gui2 import gprefs
 
diff --git a/src/calibre/customize/builtins.py b/src/calibre/customize/builtins.py
index 297169a7e5..52ea221a46 100644
--- a/src/calibre/customize/builtins.py
+++ b/src/calibre/customize/builtins.py
@@ -1,12 +1,13 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, glob
-from calibre.customize import (FileTypePlugin, MetadataReaderPlugin,
-    MetadataWriterPlugin, PreferencesPlugin, InterfaceActionBase, StoreBase)
+import glob
+import os
+
 from calibre.constants import numeric_version
-from calibre.ebooks.metadata.archive import ArchiveExtract, KPFExtract, get_comic_metadata
+from calibre.customize import FileTypePlugin, InterfaceActionBase, MetadataReaderPlugin, MetadataWriterPlugin, PreferencesPlugin, StoreBase
 from calibre.ebooks.html.to_zip import HTML2ZIP
+from calibre.ebooks.metadata.archive import ArchiveExtract, KPFExtract, get_comic_metadata
 
 plugins = []
 
@@ -588,47 +589,45 @@ plugins += [x for x in list(locals().values()) if isinstance(x, type) and
 # }}}
 
 # Conversion plugins {{{
+from calibre.ebooks.conversion.plugins.azw4_input import AZW4Input
+from calibre.ebooks.conversion.plugins.chm_input import CHMInput
 from calibre.ebooks.conversion.plugins.comic_input import ComicInput
 from calibre.ebooks.conversion.plugins.djvu_input import DJVUInput
+from calibre.ebooks.conversion.plugins.docx_input import DOCXInput
+from calibre.ebooks.conversion.plugins.docx_output import DOCXOutput
 from calibre.ebooks.conversion.plugins.epub_input import EPUBInput
+from calibre.ebooks.conversion.plugins.epub_output import EPUBOutput
 from calibre.ebooks.conversion.plugins.fb2_input import FB2Input
+from calibre.ebooks.conversion.plugins.fb2_output import FB2Output
 from calibre.ebooks.conversion.plugins.html_input import HTMLInput
+from calibre.ebooks.conversion.plugins.html_output import HTMLOutput
 from calibre.ebooks.conversion.plugins.htmlz_input import HTMLZInput
+from calibre.ebooks.conversion.plugins.htmlz_output import HTMLZOutput
 from calibre.ebooks.conversion.plugins.lit_input import LITInput
+from calibre.ebooks.conversion.plugins.lit_output import LITOutput
+from calibre.ebooks.conversion.plugins.lrf_input import LRFInput
+from calibre.ebooks.conversion.plugins.lrf_output import LRFOutput
 from calibre.ebooks.conversion.plugins.mobi_input import MOBIInput
+from calibre.ebooks.conversion.plugins.mobi_output import AZW3Output, MOBIOutput
 from calibre.ebooks.conversion.plugins.odt_input import ODTInput
+from calibre.ebooks.conversion.plugins.oeb_output import OEBOutput
 from calibre.ebooks.conversion.plugins.pdb_input import PDBInput
-from calibre.ebooks.conversion.plugins.azw4_input import AZW4Input
+from calibre.ebooks.conversion.plugins.pdb_output import PDBOutput
 from calibre.ebooks.conversion.plugins.pdf_input import PDFInput
+from calibre.ebooks.conversion.plugins.pdf_output import PDFOutput
 from calibre.ebooks.conversion.plugins.pml_input import PMLInput
+from calibre.ebooks.conversion.plugins.pml_output import PMLOutput
 from calibre.ebooks.conversion.plugins.rb_input import RBInput
+from calibre.ebooks.conversion.plugins.rb_output import RBOutput
 from calibre.ebooks.conversion.plugins.recipe_input import RecipeInput
 from calibre.ebooks.conversion.plugins.rtf_input import RTFInput
-from calibre.ebooks.conversion.plugins.tcr_input import TCRInput
-from calibre.ebooks.conversion.plugins.txt_input import TXTInput
-from calibre.ebooks.conversion.plugins.lrf_input import LRFInput
-from calibre.ebooks.conversion.plugins.chm_input import CHMInput
-from calibre.ebooks.conversion.plugins.snb_input import SNBInput
-from calibre.ebooks.conversion.plugins.docx_input import DOCXInput
-
-from calibre.ebooks.conversion.plugins.epub_output import EPUBOutput
-from calibre.ebooks.conversion.plugins.fb2_output import FB2Output
-from calibre.ebooks.conversion.plugins.lit_output import LITOutput
-from calibre.ebooks.conversion.plugins.lrf_output import LRFOutput
-from calibre.ebooks.conversion.plugins.mobi_output import (MOBIOutput,
-        AZW3Output)
-from calibre.ebooks.conversion.plugins.oeb_output import OEBOutput
-from calibre.ebooks.conversion.plugins.pdb_output import PDBOutput
-from calibre.ebooks.conversion.plugins.pdf_output import PDFOutput
-from calibre.ebooks.conversion.plugins.pml_output import PMLOutput
-from calibre.ebooks.conversion.plugins.rb_output import RBOutput
 from calibre.ebooks.conversion.plugins.rtf_output import RTFOutput
-from calibre.ebooks.conversion.plugins.tcr_output import TCROutput
-from calibre.ebooks.conversion.plugins.txt_output import TXTOutput, TXTZOutput
-from calibre.ebooks.conversion.plugins.html_output import HTMLOutput
-from calibre.ebooks.conversion.plugins.htmlz_output import HTMLZOutput
+from calibre.ebooks.conversion.plugins.snb_input import SNBInput
 from calibre.ebooks.conversion.plugins.snb_output import SNBOutput
-from calibre.ebooks.conversion.plugins.docx_output import DOCXOutput
+from calibre.ebooks.conversion.plugins.tcr_input import TCRInput
+from calibre.ebooks.conversion.plugins.tcr_output import TCROutput
+from calibre.ebooks.conversion.plugins.txt_input import TXTInput
+from calibre.ebooks.conversion.plugins.txt_output import TXTOutput, TXTZOutput
 
 plugins += [
     ComicInput,
@@ -677,57 +676,92 @@ plugins += [
 # }}}
 
 # Catalog plugins {{{
-from calibre.library.catalogs.csv_xml import CSV_XML
 from calibre.library.catalogs.bibtex import BIBTEX
+from calibre.library.catalogs.csv_xml import CSV_XML
 from calibre.library.catalogs.epub_mobi import EPUB_MOBI
+
 plugins += [CSV_XML, BIBTEX, EPUB_MOBI]
 # }}}
 
 # Profiles {{{
 from calibre.customize.profiles import input_profiles, output_profiles
+
 plugins += input_profiles + output_profiles
 # }}}
 
 # Device driver plugins {{{
-from calibre.devices.hanlin.driver import HANLINV3, HANLINV5, BOOX, SPECTRA
+from calibre.devices.android.driver import ANDROID, S60, WEBOS
+from calibre.devices.binatone.driver import README
 from calibre.devices.blackberry.driver import BLACKBERRY, PLAYBOOK
-from calibre.devices.cybook.driver import CYBOOK, ORIZON, MUSE, DIVA
-from calibre.devices.eb600.driver import (EB600, COOL_ER, SHINEBOOK, TOLINO,
-                POCKETBOOK360, GER2, ITALICA, ECLICTO, DBOOK, INVESBOOK,
-                BOOQ, ELONEX, POCKETBOOK301, MENTOR, POCKETBOOK602,
-                POCKETBOOK701, POCKETBOOK740, POCKETBOOK360P, PI2, POCKETBOOK622,
-                POCKETBOOKHD)
+from calibre.devices.boeye.driver import BOEYE_BDX, BOEYE_BEX
+from calibre.devices.cybook.driver import CYBOOK, DIVA, MUSE, ORIZON
+from calibre.devices.eb600.driver import (
+    BOOQ,
+    COOL_ER,
+    DBOOK,
+    EB600,
+    ECLICTO,
+    ELONEX,
+    GER2,
+    INVESBOOK,
+    ITALICA,
+    MENTOR,
+    PI2,
+    POCKETBOOK301,
+    POCKETBOOK360,
+    POCKETBOOK360P,
+    POCKETBOOK602,
+    POCKETBOOK622,
+    POCKETBOOK701,
+    POCKETBOOK740,
+    POCKETBOOKHD,
+    SHINEBOOK,
+    TOLINO,
+)
+from calibre.devices.edge.driver import EDGE
+from calibre.devices.eslick.driver import EBK52, ESLICK
+from calibre.devices.folder_device.driver import FOLDER_DEVICE_FOR_CONFIG
+from calibre.devices.hanlin.driver import BOOX, HANLINV3, HANLINV5, SPECTRA
+from calibre.devices.hanvon.driver import ALEX, AZBOOKA, EB511, KIBANO, LIBREAIR, N516, ODYSSEY, THEBOOK
 from calibre.devices.iliad.driver import ILIAD
-from calibre.devices.irexdr.driver import IREXDR1000, IREXDR800
-from calibre.devices.jetbook.driver import (JETBOOK, MIBUK, JETBOOK_MINI,
-        JETBOOK_COLOR)
-from calibre.devices.kindle.driver import (KINDLE, KINDLE2, KINDLE_DX,
-        KINDLE_FIRE)
+from calibre.devices.irexdr.driver import IREXDR800, IREXDR1000
+from calibre.devices.iriver.driver import IRIVER_STORY
+from calibre.devices.jetbook.driver import JETBOOK, JETBOOK_COLOR, JETBOOK_MINI, MIBUK
+from calibre.devices.kindle.driver import KINDLE, KINDLE2, KINDLE_DX, KINDLE_FIRE
+from calibre.devices.kobo.driver import KOBO, KOBOTOUCH
+from calibre.devices.misc import (
+    ADAM,
+    ALURATEK_COLOR,
+    AVANT,
+    CERVANTES,
+    COBY,
+    EEEREADER,
+    EX124G,
+    GEMEI,
+    LUMIREAD,
+    MOOVYBOOK,
+    NEXTBOOK,
+    PALMPRE,
+    PDNOVEL,
+    PDNOVEL_KOBO,
+    POCKETBOOK626,
+    SONYDPTS1,
+    SWEEX,
+    TREKSTOR,
+    VELOCITYMICRO,
+    WAYTEQ,
+    WOXTER,
+)
+from calibre.devices.mtp.driver import MTP_DEVICE
+from calibre.devices.nokia.driver import E52, E71X, N770, N810
 from calibre.devices.nook.driver import NOOK, NOOK_COLOR
+from calibre.devices.nuut2.driver import NUUT2
 from calibre.devices.prs505.driver import PRS505
 from calibre.devices.prst1.driver import PRST1
-from calibre.devices.user_defined.driver import USER_DEFINED
-from calibre.devices.android.driver import ANDROID, S60, WEBOS
-from calibre.devices.nokia.driver import N770, N810, E71X, E52
-from calibre.devices.eslick.driver import ESLICK, EBK52
-from calibre.devices.nuut2.driver import NUUT2
-from calibre.devices.iriver.driver import IRIVER_STORY
-from calibre.devices.binatone.driver import README
-from calibre.devices.hanvon.driver import (N516, EB511, ALEX, AZBOOKA, THEBOOK,
-        LIBREAIR, ODYSSEY, KIBANO)
-from calibre.devices.edge.driver import EDGE
-from calibre.devices.teclast.driver import (TECLAST_K3, NEWSMY, IPAPYRUS,
-        SOVOS, PICO, SUNSTECH_EB700, ARCHOS7O, STASH, WEXLER)
-from calibre.devices.sne.driver import SNE
-from calibre.devices.misc import (
-    PALMPRE, AVANT, SWEEX, PDNOVEL, GEMEI, VELOCITYMICRO, PDNOVEL_KOBO,
-    LUMIREAD, ALURATEK_COLOR, TREKSTOR, EEEREADER, NEXTBOOK, ADAM, MOOVYBOOK,
-    COBY, EX124G, WAYTEQ, WOXTER, POCKETBOOK626, SONYDPTS1, CERVANTES)
-from calibre.devices.folder_device.driver import FOLDER_DEVICE_FOR_CONFIG
-from calibre.devices.kobo.driver import KOBO, KOBOTOUCH
-from calibre.devices.boeye.driver import BOEYE_BEX, BOEYE_BDX
 from calibre.devices.smart_device_app.driver import SMART_DEVICE_APP
-from calibre.devices.mtp.driver import MTP_DEVICE
+from calibre.devices.sne.driver import SNE
+from calibre.devices.teclast.driver import ARCHOS7O, IPAPYRUS, NEWSMY, PICO, SOVOS, STASH, SUNSTECH_EB700, TECLAST_K3, WEXLER
+from calibre.devices.user_defined.driver import USER_DEFINED
 
 # Order here matters. The first matched device is the one used.
 plugins += [
@@ -805,12 +839,12 @@ plugins += [
 # }}}
 
 # New metadata download plugins {{{
-from calibre.ebooks.metadata.sources.google import GoogleBooks
 from calibre.ebooks.metadata.sources.amazon import Amazon
-from calibre.ebooks.metadata.sources.edelweiss import Edelweiss
-from calibre.ebooks.metadata.sources.openlibrary import OpenLibrary
-from calibre.ebooks.metadata.sources.google_images import GoogleImages
 from calibre.ebooks.metadata.sources.big_book_search import BigBookSearch
+from calibre.ebooks.metadata.sources.edelweiss import Edelweiss
+from calibre.ebooks.metadata.sources.google import GoogleBooks
+from calibre.ebooks.metadata.sources.google_images import GoogleImages
+from calibre.ebooks.metadata.sources.openlibrary import OpenLibrary
 
 plugins += [GoogleBooks, GoogleImages, Amazon, Edelweiss, OpenLibrary, BigBookSearch]
 
@@ -1936,7 +1970,8 @@ plugins += [
 
 if __name__ == '__main__':
     # Test load speed
-    import subprocess, textwrap
+    import subprocess
+    import textwrap
     try:
         subprocess.check_call(['python', '-c', textwrap.dedent(
         '''
diff --git a/src/calibre/customize/conversion.py b/src/calibre/customize/conversion.py
index aa2dd48b9e..efeff90636 100644
--- a/src/calibre/customize/conversion.py
+++ b/src/calibre/customize/conversion.py
@@ -1,7 +1,10 @@
 '''
 Defines the plugin system for conversions.
 '''
-import re, os, shutil, numbers
+import numbers
+import os
+import re
+import shutil
 
 from calibre import CurrentDir
 from calibre.customize import Plugin
diff --git a/src/calibre/customize/ui.py b/src/calibre/customize/ui.py
index 84a6169065..f4e0285f34 100644
--- a/src/calibre/customize/ui.py
+++ b/src/calibre/customize/ui.py
@@ -1,26 +1,38 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, shutil, traceback, functools, sys
+import functools
+import os
+import shutil
+import sys
+import traceback
 from collections import defaultdict
 from itertools import chain, repeat
 
-from calibre.customize import (CatalogPlugin, FileTypePlugin, PluginNotFound,
-                              MetadataReaderPlugin, MetadataWriterPlugin,
-                              InterfaceActionBase as InterfaceAction,
-                              PreferencesPlugin, platform, InvalidPlugin,
-                              StoreBase as Store, EditBookToolPlugin,
-                              LibraryClosedPlugin, PluginInstallationType)
-from calibre.customize.conversion import InputFormatPlugin, OutputFormatPlugin
-from calibre.customize.zipplugin import loader
-from calibre.customize.profiles import InputProfile, OutputProfile
+from calibre.constants import DEBUG, ismacos, numeric_version, system_plugins_loc
+from calibre.customize import (
+    CatalogPlugin,
+    EditBookToolPlugin,
+    FileTypePlugin,
+    InvalidPlugin,
+    LibraryClosedPlugin,
+    MetadataReaderPlugin,
+    MetadataWriterPlugin,
+    PluginInstallationType,
+    PluginNotFound,
+    PreferencesPlugin,
+    platform,
+)
+from calibre.customize import InterfaceActionBase as InterfaceAction
+from calibre.customize import StoreBase as Store
 from calibre.customize.builtins import plugins as builtin_plugins
+from calibre.customize.conversion import InputFormatPlugin, OutputFormatPlugin
+from calibre.customize.profiles import InputProfile, OutputProfile
+from calibre.customize.zipplugin import loader
 from calibre.devices.interface import DevicePlugin
 from calibre.ebooks.metadata import MetaInformation
-from calibre.utils.config import (make_config_dir, Config, ConfigProxy,
-                                 plugin_dir, OptionParser)
 from calibre.ebooks.metadata.sources.base import Source
-from calibre.constants import DEBUG, numeric_version, system_plugins_loc, ismacos
+from calibre.utils.config import Config, ConfigProxy, OptionParser, make_config_dir, plugin_dir
 from polyglot.builtins import iteritems, itervalues
 
 builtin_names = frozenset(p.name for p in builtin_plugins)
@@ -757,8 +769,8 @@ def initialize_plugins(perf=False):
         system_plugins.pop(name, None)
     ostdout, ostderr = sys.stdout, sys.stderr
     if perf:
-        from collections import defaultdict
         import time
+        from collections import defaultdict
         times = defaultdict(int)
 
     for zfp, installation_type in chain(
@@ -815,7 +827,7 @@ def initialized_plugins():
 def build_plugin(path):
     from calibre import prints
     from calibre.ptempfile import PersistentTemporaryFile
-    from calibre.utils.zipfile import ZipFile, ZIP_STORED
+    from calibre.utils.zipfile import ZIP_STORED, ZipFile
     path = str(path)
     names = frozenset(os.listdir(path))
     if '__init__.py' not in names:
diff --git a/src/calibre/customize/zipplugin.py b/src/calibre/customize/zipplugin.py
index aad3d83f90..efb988d005 100644
--- a/src/calibre/customize/zipplugin.py
+++ b/src/calibre/customize/zipplugin.py
@@ -18,9 +18,7 @@ from importlib.machinery import ModuleSpec
 from importlib.util import decode_source
 
 from calibre import as_unicode
-from calibre.customize import (
-    InvalidPlugin, Plugin, PluginNotFound, numeric_version, platform
-)
+from calibre.customize import InvalidPlugin, Plugin, PluginNotFound, numeric_version, platform
 from polyglot.builtins import itervalues, reload, string_or_bytes
 
 
diff --git a/src/calibre/db/__init__.py b/src/calibre/db/__init__.py
index 1b9c618cf6..05481f3625 100644
--- a/src/calibre/db/__init__.py
+++ b/src/calibre/db/__init__.py
@@ -8,6 +8,7 @@ __docformat__ = 'restructuredtext en'
 SPOOL_SIZE = 30*1024*1024
 
 import numbers
+
 from polyglot.builtins import iteritems
 
 
@@ -20,8 +21,9 @@ class FTSQueryError(ValueError):
 
 
 def _get_next_series_num_for_list(series_indices, unwrap=True):
-    from calibre.utils.config_base import tweaks
     from math import ceil, floor
+
+    from calibre.utils.config_base import tweaks
     if not series_indices:
         if isinstance(tweaks['series_index_auto_increment'], numbers.Number):
             return float(tweaks['series_index_auto_increment'])
@@ -77,6 +79,7 @@ def get_data_as_dict(self, prefix=None, authors_as_string=False, ids=None, conve
     all entries in database.
     '''
     import os
+
     from calibre.ebooks.metadata import authors_to_string
     from calibre.utils.date import as_local_time
     backend = getattr(self, 'backend', self)  # Works with both old and legacy interfaces
diff --git a/src/calibre/db/backend.py b/src/calibre/db/backend.py
index 4e79368bd6..b75ab5c45b 100644
--- a/src/calibre/db/backend.py
+++ b/src/calibre/db/backend.py
@@ -6,7 +6,6 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 # Imports {{{
-import apsw
 import errno
 import hashlib
 import json
@@ -17,48 +16,64 @@ import sys
 import time
 import uuid
 from contextlib import closing, suppress
-from typing import Optional
 from functools import partial
+from typing import Optional
+
+import apsw
 
 from calibre import as_unicode, force_unicode, isbytestring, prints
-from calibre.constants import (
-    filesystem_encoding, iswindows, plugins, preferred_encoding,
-)
+from calibre.constants import filesystem_encoding, iswindows, plugins, preferred_encoding
 from calibre.db import SPOOL_SIZE, FTSQueryError
 from calibre.db.annotations import annot_db_data, unicode_normalize
 from calibre.db.constants import (
-    BOOK_ID_PATH_TEMPLATE, COVER_FILE_NAME, DEFAULT_TRASH_EXPIRY_TIME_SECONDS,
-    METADATA_FILE_NAME, NOTES_DIR_NAME, TRASH_DIR_NAME, TrashEntry,
+    BOOK_ID_PATH_TEMPLATE,
+    COVER_FILE_NAME,
+    DEFAULT_TRASH_EXPIRY_TIME_SECONDS,
+    METADATA_FILE_NAME,
+    NOTES_DIR_NAME,
+    TRASH_DIR_NAME,
+    TrashEntry,
 )
 from calibre.db.errors import NoSuchFormat
 from calibre.db.schema_upgrades import SchemaUpgrade
 from calibre.db.tables import (
-    AuthorsTable, CompositeTable, FormatsTable, IdentifiersTable, ManyToManyTable,
-    ManyToOneTable, OneToOneTable, PathTable, RatingTable, SizeTable, UUIDTable,
+    AuthorsTable,
+    CompositeTable,
+    FormatsTable,
+    IdentifiersTable,
+    ManyToManyTable,
+    ManyToOneTable,
+    OneToOneTable,
+    PathTable,
+    RatingTable,
+    SizeTable,
+    UUIDTable,
 )
 from calibre.ebooks.metadata import author_to_author_sort, title_sort
 from calibre.library.field_metadata import FieldMetadata
 from calibre.ptempfile import PersistentTemporaryFile, TemporaryFile
 from calibre.utils import pickle_binary_string, unpickle_binary_string
 from calibre.utils.config import from_json, prefs, to_json, tweaks
-from calibre.utils.copy_files import (
-    copy_files, copy_tree, rename_files, windows_check_if_files_in_use,
-)
+from calibre.utils.copy_files import copy_files, copy_tree, rename_files, windows_check_if_files_in_use
 from calibre.utils.date import EPOCH, parse_date, utcfromtimestamp, utcnow
 from calibre.utils.filenames import (
-    ascii_filename, atomic_rename, copyfile_using_links, copytree_using_links,
-    get_long_path_name, hardlink_file, is_case_sensitive, is_fat_filesystem,
-    make_long_path_useable, remove_dir_if_empty, samefile,
+    ascii_filename,
+    atomic_rename,
+    copyfile_using_links,
+    copytree_using_links,
+    get_long_path_name,
+    hardlink_file,
+    is_case_sensitive,
+    is_fat_filesystem,
+    make_long_path_useable,
+    remove_dir_if_empty,
+    samefile,
 )
-from calibre.utils.formatter_functions import (
-    compile_user_template_functions, formatter_functions, load_user_template_functions,
-    unload_user_template_functions,
-)
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.formatter_functions import compile_user_template_functions, formatter_functions, load_user_template_functions, unload_user_template_functions
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 from calibre.utils.resources import get_path as P
-from polyglot.builtins import (
-    cmp, iteritems, itervalues, native_string_type, reraise, string_or_bytes,
-)
+from polyglot.builtins import cmp, iteritems, itervalues, native_string_type, reraise, string_or_bytes
 
 # }}}
 
@@ -1375,6 +1390,7 @@ class DB:
 
     def dump_and_restore(self, callback=None, sql=None):
         import codecs
+
         from apsw import Shell
         if callback is None:
             def callback(x):
diff --git a/src/calibre/db/backup.py b/src/calibre/db/backup.py
index 2437d7169d..23c8429c96 100644
--- a/src/calibre/db/backup.py
+++ b/src/calibre/db/backup.py
@@ -5,8 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import weakref, traceback, sys
-from threading import Thread, Event
+import sys
+import traceback
+import weakref
+from threading import Event, Thread
 
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
 
diff --git a/src/calibre/db/cache.py b/src/calibre/db/cache.py
index 73a05d493f..a9cd3abebd 100644
--- a/src/calibre/db/cache.py
+++ b/src/calibre/db/cache.py
@@ -25,10 +25,7 @@ from typing import NamedTuple, Optional, Tuple
 
 from calibre import as_unicode, detect_ncpus, isbytestring
 from calibre.constants import iswindows, preferred_encoding
-from calibre.customize.ui import (
-    run_plugins_on_import, run_plugins_on_postadd, run_plugins_on_postdelete,
-    run_plugins_on_postimport,
-)
+from calibre.customize.ui import run_plugins_on_import, run_plugins_on_postadd, run_plugins_on_postdelete, run_plugins_on_postimport
 from calibre.db import SPOOL_SIZE, _get_next_series_num_for_list
 from calibre.db.annotations import merge_annotations
 from calibre.db.categories import get_categories
@@ -37,9 +34,7 @@ from calibre.db.errors import NoSuchBook, NoSuchFormat
 from calibre.db.fields import IDENTITY, InvalidLinkTable, create_field
 from calibre.db.lazy import FormatMetadata, FormatsList, ProxyMetadata
 from calibre.db.listeners import EventDispatcher, EventType
-from calibre.db.locking import (
-    DowngradeLockError, LockingError, SafeReadLock, create_locks, try_lock,
-)
+from calibre.db.locking import DowngradeLockError, LockingError, SafeReadLock, create_locks, try_lock
 from calibre.db.notes.connect import copy_marked_up_text
 from calibre.db.search import Search
 from calibre.db.tables import VirtualTable
@@ -51,9 +46,11 @@ from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
 from calibre.ptempfile import PersistentTemporaryFile, SpooledTemporaryFile, base_dir
 from calibre.utils.config import prefs, tweaks
-from calibre.utils.date import UNDEFINED_DATE, now as nowf, utcnow
+from calibre.utils.date import UNDEFINED_DATE, utcnow
+from calibre.utils.date import now as nowf
 from calibre.utils.filenames import make_long_path_useable
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 from calibre.utils.localization import canonicalize_lang
 from polyglot.builtins import cmp, iteritems, itervalues, string_or_bytes
 
diff --git a/src/calibre/db/categories.py b/src/calibre/db/categories.py
index dd1edefafb..b8e3f5d913 100644
--- a/src/calibre/db/categories.py
+++ b/src/calibre/db/categories.py
@@ -11,9 +11,9 @@ from functools import partial
 
 from calibre.ebooks.metadata import author_to_author_sort
 from calibre.utils.config_base import prefs, tweaks
-from calibre.utils.icu import (
-    collation_order, lower as icu_lower, sort_key, upper as icu_upper,
-)
+from calibre.utils.icu import collation_order, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 from polyglot.builtins import iteritems, native_string_type
 
 CATEGORY_SORTS = ('name', 'popularity', 'rating')  # This has to be a tuple not a set
diff --git a/src/calibre/db/cli/cmd_add.py b/src/calibre/db/cli/cmd_add.py
index 90d4c132ff..3dba096315 100644
--- a/src/calibre/db/cli/cmd_add.py
+++ b/src/calibre/db/cli/cmd_add.py
@@ -8,10 +8,7 @@ from contextlib import contextmanager
 from optparse import OptionGroup, OptionValueError
 
 from calibre import prints
-from calibre.db.adding import (
-    cdb_find_in_dir, cdb_recursive_find, compile_rule, create_format_map,
-    run_import_plugins, run_import_plugins_before_metadata
-)
+from calibre.db.adding import cdb_find_in_dir, cdb_recursive_find, compile_rule, create_format_map, run_import_plugins, run_import_plugins_before_metadata
 from calibre.db.utils import find_identical_books
 from calibre.ebooks.metadata import MetaInformation, string_to_authors
 from calibre.ebooks.metadata.book.serialize import read_cover, serialize_cover
diff --git a/src/calibre/db/cli/cmd_export.py b/src/calibre/db/cli/cmd_export.py
index e2ce552daf..a6521caf24 100644
--- a/src/calibre/db/cli/cmd_export.py
+++ b/src/calibre/db/cli/cmd_export.py
@@ -5,11 +5,9 @@
 import os
 
 from calibre.db.cli import integers_from_string
-from calibre.db.errors import NoSuchFormat
 from calibre.db.constants import DATA_FILE_PATTERN
-from calibre.library.save_to_disk import (
-    config, do_save_book_to_disk, get_formats, sanitize_args
-)
+from calibre.db.errors import NoSuchFormat
+from calibre.library.save_to_disk import config, do_save_book_to_disk, get_formats, sanitize_args
 from calibre.utils.formatter_functions import load_user_template_functions
 
 readonly = True
diff --git a/src/calibre/db/cli/cmd_fts_search.py b/src/calibre/db/cli/cmd_fts_search.py
index 27d6011be9..46b5b9cd12 100644
--- a/src/calibre/db/cli/cmd_fts_search.py
+++ b/src/calibre/db/cli/cmd_fts_search.py
@@ -102,8 +102,8 @@ Do a full text search on the entire library or a subset of it.
 
 
 def output_results_as_text(results, metadata_cache, include_snippets):
-    from calibre.utils.terminal import geometry
     from calibre.ebooks.metadata import authors_to_string
+    from calibre.utils.terminal import geometry
     width = max(5, geometry()[0])
     separator = '─' * width
     if not include_snippets:
diff --git a/src/calibre/db/cli/cmd_list_categories.py b/src/calibre/db/cli/cmd_list_categories.py
index 351d452fb4..fe9822cd31 100644
--- a/src/calibre/db/cli/cmd_list_categories.py
+++ b/src/calibre/db/cli/cmd_list_categories.py
@@ -71,7 +71,7 @@ information is the equivalent of what is shown in the Tag browser.
 
 
 def do_list(fields, data, opts):
-    from calibre.utils.terminal import geometry, ColoredStream
+    from calibre.utils.terminal import ColoredStream, geometry
 
     separator = ' '
     widths = list(map(lambda x: 0, fields))
diff --git a/src/calibre/db/cli/cmd_remove_custom_column.py b/src/calibre/db/cli/cmd_remove_custom_column.py
index 6d2f605894..9558521424 100644
--- a/src/calibre/db/cli/cmd_remove_custom_column.py
+++ b/src/calibre/db/cli/cmd_remove_custom_column.py
@@ -3,6 +3,7 @@
 
 
 import sys
+
 from calibre import prints
 from calibre.db.legacy import LibraryDatabase
 
diff --git a/src/calibre/db/cli/main.py b/src/calibre/db/cli/main.py
index 0aaaeecb0a..012e3b098f 100644
--- a/src/calibre/db/cli/main.py
+++ b/src/calibre/db/cli/main.py
@@ -195,7 +195,8 @@ class DBCtx:
 
     def remote_run(self, name, m, *args):
         from mechanize import HTTPError, Request
-        from calibre.utils.serialize import msgpack_loads, msgpack_dumps
+
+        from calibre.utils.serialize import msgpack_dumps, msgpack_loads
         url = self.url + '/cdb/cmd/{}/{}'.format(name, getattr(m, 'version', 0))
         if self.library_id:
             url += '?' + urlencode({'library_id':self.library_id})
diff --git a/src/calibre/db/fields.py b/src/calibre/db/fields.py
index a6a443efd9..54ab05132f 100644
--- a/src/calibre/db/fields.py
+++ b/src/calibre/db/fields.py
@@ -6,21 +6,20 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import sys
-from threading import Lock
-from collections import defaultdict, Counter
+from collections import Counter, defaultdict
 from functools import partial
+from threading import Lock
 
-from calibre.db.tables import ONE_ONE, MANY_ONE, MANY_MANY, null
+from calibre.db.tables import MANY_MANY, MANY_ONE, ONE_ONE, null
+from calibre.db.utils import atof, force_to_bool
 from calibre.db.write import Writer
-from calibre.db.utils import force_to_bool, atof
-from calibre.ebooks.metadata import title_sort, author_to_author_sort, rating_to_stars
+from calibre.ebooks.metadata import author_to_author_sort, rating_to_stars, title_sort
 from calibre.utils.config_base import tweaks
-from calibre.utils.icu import sort_key
 from calibre.utils.date import UNDEFINED_DATE, clean_date_for_sort, parse_date
+from calibre.utils.icu import sort_key
 from calibre.utils.localization import calibre_langcode_to_name
 from polyglot.builtins import iteritems
 
-
 rendering_composite_name = '__rendering_composite__'
 
 
diff --git a/src/calibre/db/fts/connect.py b/src/calibre/db/fts/connect.py
index e47cbc5f42..d5ebfe3aea 100644
--- a/src/calibre/db/fts/connect.py
+++ b/src/calibre/db/fts/connect.py
@@ -2,14 +2,15 @@
 # License: GPL v3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import apsw
 import builtins
 import hashlib
 import os
 import sys
 from contextlib import suppress
-from threading import Lock
 from itertools import count
+from threading import Lock
+
+import apsw
 
 from calibre.db import FTSQueryError
 from calibre.db.annotations import unicode_normalize
diff --git a/src/calibre/db/lazy.py b/src/calibre/db/lazy.py
index c9a96fd9ec..33594767e6 100644
--- a/src/calibre/db/lazy.py
+++ b/src/calibre/db/lazy.py
@@ -6,11 +6,11 @@ __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import weakref
-from functools import wraps
 from collections.abc import MutableMapping, MutableSequence
 from copy import deepcopy
+from functools import wraps
 
-from calibre.ebooks.metadata.book.base import Metadata, SIMPLE_GET, TOP_LEVEL_IDENTIFIERS, NULL_VALUES, ALL_METADATA_FIELDS
+from calibre.ebooks.metadata.book.base import ALL_METADATA_FIELDS, NULL_VALUES, SIMPLE_GET, TOP_LEVEL_IDENTIFIERS, Metadata
 from calibre.ebooks.metadata.book.formatter import SafeFormat
 from calibre.utils.date import utcnow
 from polyglot.builtins import native_string_type
diff --git a/src/calibre/db/legacy.py b/src/calibre/db/legacy.py
index a333bb3d6c..b8a9ff5d11 100644
--- a/src/calibre/db/legacy.py
+++ b/src/calibre/db/legacy.py
@@ -11,14 +11,10 @@ from collections.abc import MutableMapping
 
 from calibre import force_unicode, isbytestring
 from calibre.constants import preferred_encoding
-from calibre.db import (
-    _get_next_series_num_for_list, _get_series_values, get_data_as_dict,
-)
-from calibre.db.adding import (
-    add_catalog, add_news, find_books_in_directory, import_book_directory,
-    import_book_directory_multiple, recursive_import,
-)
-from calibre.db.backend import DB, set_global_state as backend_set_global_state
+from calibre.db import _get_next_series_num_for_list, _get_series_values, get_data_as_dict
+from calibre.db.adding import add_catalog, add_news, find_books_in_directory, import_book_directory, import_book_directory_multiple, recursive_import
+from calibre.db.backend import DB
+from calibre.db.backend import set_global_state as backend_set_global_state
 from calibre.db.cache import Cache
 from calibre.db.categories import CATEGORY_SORTS
 from calibre.db.errors import NoSuchFormat
diff --git a/src/calibre/db/listeners.py b/src/calibre/db/listeners.py
index f8d2f4a151..b6e2fb2850 100644
--- a/src/calibre/db/listeners.py
+++ b/src/calibre/db/listeners.py
@@ -3,9 +3,9 @@
 
 import weakref
 from contextlib import suppress
+from enum import Enum, auto
 from queue import Queue
 from threading import Thread
-from enum import Enum, auto
 
 
 class EventType(Enum):
diff --git a/src/calibre/db/locking.py b/src/calibre/db/locking.py
index 224e509cde..6b9d1fedf3 100644
--- a/src/calibre/db/locking.py
+++ b/src/calibre/db/locking.py
@@ -5,9 +5,11 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import traceback, sys, os
-from threading import Lock, Condition, current_thread
+import os
+import sys
+import traceback
 from contextlib import contextmanager
+from threading import Condition, Lock, current_thread
 
 
 @contextmanager
diff --git a/src/calibre/db/notes/connect.py b/src/calibre/db/notes/connect.py
index 6d984f9835..c0f0a68b72 100644
--- a/src/calibre/db/notes/connect.py
+++ b/src/calibre/db/notes/connect.py
@@ -1,17 +1,18 @@
 #!/usr/bin/env python
 # License: GPLv3 Copyright: 2023, Kovid Goyal <kovid at kovidgoyal.net>
 
-import apsw
 import json
 import os
 import shutil
 import time
-import xxhash
+from collections import defaultdict
 from contextlib import suppress
 from itertools import count, repeat
-from collections import defaultdict
 from typing import Optional
 
+import apsw
+import xxhash
+
 from calibre import sanitize_file_name
 from calibre.constants import iswindows
 from calibre.db import FTSQueryError
@@ -20,8 +21,8 @@ from calibre.utils.copy_files import WINDOWS_SLEEP_FOR_RETRY_TIME
 from calibre.utils.filenames import copyfile_using_links, make_long_path_useable
 from calibre.utils.icu import lower as icu_lower
 
-from ..constants import NOTES_DB_NAME, NOTES_DIR_NAME
 from .schema_upgrade import SchemaUpgrade
+from ..constants import NOTES_DB_NAME, NOTES_DIR_NAME
 
 if iswindows:
     from calibre_extensions import winutil
diff --git a/src/calibre/db/notes/exim.py b/src/calibre/db/notes/exim.py
index c55854b536..b5516ab774 100644
--- a/src/calibre/db/notes/exim.py
+++ b/src/calibre/db/notes/exim.py
@@ -3,9 +3,10 @@
 
 import base64
 import os
+from urllib.parse import unquote, urlparse
+
 from html5_parser import parse
 from lxml import html
-from urllib.parse import unquote, urlparse
 
 from calibre import guess_extension, guess_type
 from calibre.db.constants import RESOURCE_URL_SCHEME
diff --git a/src/calibre/db/restore.py b/src/calibre/db/restore.py
index 1025697e4a..7ba72f8950 100644
--- a/src/calibre/db/restore.py
+++ b/src/calibre/db/restore.py
@@ -18,8 +18,8 @@ from threading import Thread
 from calibre import force_unicode, isbytestring
 from calibre.constants import filesystem_encoding, iswindows
 from calibre.db.backend import DB, DBPrefs
-from calibre.db.constants import METADATA_FILE_NAME, TRASH_DIR_NAME, NOTES_DIR_NAME, NOTES_DB_NAME
 from calibre.db.cache import Cache
+from calibre.db.constants import METADATA_FILE_NAME, NOTES_DB_NAME, NOTES_DIR_NAME, TRASH_DIR_NAME
 from calibre.ebooks.metadata.opf2 import OPF
 from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.date import utcfromtimestamp
diff --git a/src/calibre/db/schema_upgrades.py b/src/calibre/db/schema_upgrades.py
index 4c395a8d3f..6e9a9ef318 100644
--- a/src/calibre/db/schema_upgrades.py
+++ b/src/calibre/db/schema_upgrades.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 import os
 
 from calibre import prints
-from calibre.utils.date import isoformat, DEFAULT_DATE
+from calibre.utils.date import DEFAULT_DATE, isoformat
 from polyglot.builtins import itervalues
 
 
@@ -590,8 +590,7 @@ class SchemaUpgrade:
     def upgrade_version_19(self):
         recipes = self.db.get('SELECT id,title,script FROM feeds')
         if recipes:
-            from calibre.web.feeds.recipes import (custom_recipes,
-                    custom_recipe_filename)
+            from calibre.web.feeds.recipes import custom_recipe_filename, custom_recipes
             bdir = os.path.dirname(custom_recipes.file_path)
             for id_, title, script in recipes:
                 existing = frozenset(map(int, custom_recipes))
diff --git a/src/calibre/db/search.py b/src/calibre/db/search.py
index 1153139791..ee3ed6edd0 100644
--- a/src/calibre/db/search.py
+++ b/src/calibre/db/search.py
@@ -6,19 +6,19 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import operator
-import regex
 import weakref
 from collections import OrderedDict, deque
 from datetime import timedelta
 from functools import partial
 
+import regex
+
 from calibre.constants import DEBUG, preferred_encoding
 from calibre.db.utils import force_to_bool
 from calibre.utils.config_base import prefs
 from calibre.utils.date import UNDEFINED_DATE, dt_as_local, now, parse_date
-from calibre.utils.icu import (
-    lower as icu_lower, primary_contains, primary_no_punc_contains, sort_key,
-)
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import primary_contains, primary_no_punc_contains, sort_key
 from calibre.utils.localization import canonicalize_lang, lang_map
 from calibre.utils.search_query_parser import ParseException, SearchQueryParser
 from polyglot.builtins import iteritems, string_or_bytes
diff --git a/src/calibre/db/tests/filesystem.py b/src/calibre/db/tests/filesystem.py
index cea9c5d795..2cae7f0c35 100644
--- a/src/calibre/db/tests/filesystem.py
+++ b/src/calibre/db/tests/filesystem.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import unittest, os, time
+import os
+import time
+import unittest
 from io import BytesIO
 
 from calibre.constants import iswindows
@@ -174,7 +176,7 @@ class FilesystemTest(BaseTest):
 
         # Test on folder with hardlinks
         from calibre.ptempfile import TemporaryDirectory
-        from calibre.utils.filenames import hardlink_file, WindowsAtomicFolderMove
+        from calibre.utils.filenames import WindowsAtomicFolderMove, hardlink_file
         raw = b'xxx'
         with TemporaryDirectory() as tdir1, TemporaryDirectory() as tdir2:
             a, b = os.path.join(tdir1, 'a'), os.path.join(tdir1, 'b')
@@ -296,7 +298,7 @@ class FilesystemTest(BaseTest):
             self.assertLess(abs(at-bt), 2)
 
     def test_find_books_in_directory(self):
-        from calibre.db.adding import find_books_in_directory, compile_rule
+        from calibre.db.adding import compile_rule, find_books_in_directory
         def strip(files):
             return frozenset({os.path.basename(x) for x in files})
 
diff --git a/src/calibre/db/tests/fts.py b/src/calibre/db/tests/fts.py
index 36983ed9ef..b607be21ba 100644
--- a/src/calibre/db/tests/fts.py
+++ b/src/calibre/db/tests/fts.py
@@ -6,6 +6,7 @@ import builtins
 import os
 import sys
 import tempfile
+
 from apsw import Connection
 
 from calibre.constants import plugins
@@ -71,7 +72,7 @@ class FTSTest(BaseTest):
         set_ui_language('en')
 
     def test_fts_tokenize(self):  # {{{
-        from calibre_extensions.sqlite_extension import set_ui_language, FTS5_TOKENIZE_QUERY, FTS5_TOKENIZE_DOCUMENT
+        from calibre_extensions.sqlite_extension import FTS5_TOKENIZE_DOCUMENT, FTS5_TOKENIZE_QUERY, set_ui_language
 
         def t(x, s, e, f=0):
             return {'text': x, 'start': s, 'end': e, 'flags': f}
diff --git a/src/calibre/db/tests/fts_api.py b/src/calibre/db/tests/fts_api.py
index e482c3ade9..42ae209537 100644
--- a/src/calibre/db/tests/fts_api.py
+++ b/src/calibre/db/tests/fts_api.py
@@ -8,8 +8,8 @@ import shutil
 import sys
 import time
 from io import BytesIO, StringIO
-from zipfile import ZipFile
 from unittest.mock import patch
+from zipfile import ZipFile
 
 from calibre.db.fts.text import html_to_text
 from calibre.db.tests.base import BaseTest
@@ -25,8 +25,8 @@ class FTSAPITest(BaseTest):
 
     def setUp(self):
         super().setUp()
-        from calibre_extensions.sqlite_extension import set_ui_language
         from calibre.db.cache import Cache
+        from calibre_extensions.sqlite_extension import set_ui_language
         self.orig_sleep_time = Cache.fts_indexing_sleep_time
         Cache.fts_indexing_sleep_time = 0
         set_ui_language('en')
@@ -35,8 +35,8 @@ class FTSAPITest(BaseTest):
     def tearDown(self):
         [c.close() for c in self.libraries_to_close]
         super().tearDown()
-        from calibre_extensions.sqlite_extension import set_ui_language
         from calibre.db.cache import Cache
+        from calibre_extensions.sqlite_extension import set_ui_language
         Cache.fts_indexing_sleep_time = self.orig_sleep_time
         set_ui_language('en')
 
diff --git a/src/calibre/db/tests/locking.py b/src/calibre/db/tests/locking.py
index c568a7ac3e..56eaf7c52c 100644
--- a/src/calibre/db/tests/locking.py
+++ b/src/calibre/db/tests/locking.py
@@ -4,10 +4,12 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import time, random
+import random
+import time
 from threading import Thread
+
+from calibre.db.locking import LockingError, RWLockWrapper, SHLock
 from calibre.db.tests.base import BaseTest
-from calibre.db.locking import SHLock, RWLockWrapper, LockingError
 
 
 def wait_for(period):
diff --git a/src/calibre/db/tests/profiling.py b/src/calibre/db/tests/profiling.py
index 122b89a516..3732c8ec47 100644
--- a/src/calibre/db/tests/profiling.py
+++ b/src/calibre/db/tests/profiling.py
@@ -4,7 +4,8 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, cProfile
+import cProfile
+import os
 from tempfile import gettempdir
 
 from calibre.db.legacy import LibraryDatabase
diff --git a/src/calibre/db/tests/reading.py b/src/calibre/db/tests/reading.py
index 3f3f6acfb8..411f05fe7c 100644
--- a/src/calibre/db/tests/reading.py
+++ b/src/calibre/db/tests/reading.py
@@ -5,13 +5,14 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import datetime, os
+import datetime
+import os
 from io import BytesIO
 from time import time
 
+from calibre.db.tests.base import BaseTest
 from calibre.utils.date import utc_tz
 from calibre.utils.localization import calibre_langcode_to_name
-from calibre.db.tests.base import BaseTest
 from polyglot.builtins import iteritems, itervalues
 
 
@@ -244,8 +245,8 @@ class ReadingTest(BaseTest):
     # }}}
 
     def test_serialize_metadata(self):  # {{{
-        from calibre.utils.serialize import json_dumps, json_loads, msgpack_dumps, msgpack_loads
         from calibre.library.field_metadata import fm_as_dict
+        from calibre.utils.serialize import json_dumps, json_loads, msgpack_dumps, msgpack_loads
         cache = self.init_cache(self.library_path)
         fm = cache.field_metadata
         for d, l in ((json_dumps, json_loads), (msgpack_dumps, msgpack_loads)):
@@ -427,8 +428,8 @@ class ReadingTest(BaseTest):
 
     def test_get_formats(self):  # {{{
         'Test reading ebook formats using the format() method'
-        from calibre.library.database2 import LibraryDatabase2
         from calibre.db.cache import NoSuchFormat
+        from calibre.library.database2 import LibraryDatabase2
         old = LibraryDatabase2(self.library_path)
         ids = old.all_ids()
         lf = {i:set(old.formats(i, index_is_id=True).split(',')) if old.formats(
@@ -515,8 +516,8 @@ class ReadingTest(BaseTest):
 
     def test_datetime(self):  # {{{
         ' Test the reading of datetimes stored in the db '
+        from calibre.db.tables import UNDEFINED_DATE, _c_speedup, c_parse
         from calibre.utils.date import parse_date
-        from calibre.db.tables import c_parse, UNDEFINED_DATE, _c_speedup
 
         # First test parsing of string to UTC time
         for raw in ('2013-07-22 15:18:29+05:30', '  2013-07-22 15:18:29+00:00', '2013-07-22 15:18:29', '2003-09-21 23:30:00-06:00'):
@@ -775,8 +776,8 @@ class ReadingTest(BaseTest):
 
     def test_find_identical_books(self):  # {{{
         ' Test find_identical_books '
-        from calibre.ebooks.metadata.book.base import Metadata
         from calibre.db.utils import find_identical_books
+        from calibre.ebooks.metadata.book.base import Metadata
         # 'find_identical_books': [(,), (Metadata('unknown'),), (Metadata('xxxx'),)],
         cache = self.init_cache(self.library_path)
         cache.set_field('languages', {1: ('fra', 'deu')})
@@ -941,8 +942,7 @@ def evaluate(book, ctx):
         self.assertEqual(set(v.split(',')), {'Tag One', 'News', 'Tag Two'})
 
         # test calling a python stored template from a GPM template
-        from calibre.utils.formatter_functions import (
-                load_user_template_functions, unload_user_template_functions)
+        from calibre.utils.formatter_functions import load_user_template_functions, unload_user_template_functions
         load_user_template_functions('aaaaa',
                                      [['python_stored_template',
                                       "",
diff --git a/src/calibre/db/utils.py b/src/calibre/db/utils.py
index 6b29971301..1442253ebf 100644
--- a/src/calibre/db/utils.py
+++ b/src/calibre/db/utils.py
@@ -15,9 +15,7 @@ from locale import localeconv
 from threading import Lock
 
 from calibre import as_unicode, prints
-from calibre.constants import (
-    cache_dir, get_windows_number_formats, iswindows, preferred_encoding,
-)
+from calibre.constants import cache_dir, get_windows_number_formats, iswindows, preferred_encoding
 from calibre.utils.icu import lower as icu_lower
 from calibre.utils.localization import canonicalize_lang
 from polyglot.builtins import iteritems, itervalues, string_or_bytes
diff --git a/src/calibre/db/view.py b/src/calibre/db/view.py
index f42ab82ae7..8f28c6a9b6 100644
--- a/src/calibre/db/view.py
+++ b/src/calibre/db/view.py
@@ -5,13 +5,16 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import weakref, operator, numbers, sys
+import numbers
+import operator
+import sys
+import weakref
 from functools import partial
-from polyglot.builtins import iteritems, itervalues
 
-from calibre.ebooks.metadata import title_sort
-from calibre.utils.config_base import tweaks, prefs
 from calibre.db.write import uniq
+from calibre.ebooks.metadata import title_sort
+from calibre.utils.config_base import prefs, tweaks
+from polyglot.builtins import iteritems, itervalues
 
 
 def sanitize_sort_field_name(field_metadata, field):
diff --git a/src/calibre/db/write.py b/src/calibre/db/write.py
index af5d1b9a14..61319fef4b 100644
--- a/src/calibre/db/write.py
+++ b/src/calibre/db/write.py
@@ -11,10 +11,9 @@ from functools import partial
 
 from calibre.constants import preferred_encoding
 from calibre.ebooks.metadata import author_to_author_sort, title_sort
-from calibre.utils.date import (
-    UNDEFINED_DATE, is_date_undefined, isoformat, parse_date, parse_only_date,
-)
-from calibre.utils.icu import lower as icu_lower, strcmp
+from calibre.utils.date import UNDEFINED_DATE, is_date_undefined, isoformat, parse_date, parse_only_date
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import strcmp
 from calibre.utils.localization import canonicalize_lang
 from polyglot.builtins import iteritems, itervalues
 
diff --git a/src/calibre/debug.py b/src/calibre/debug.py
index f44c80e6dd..36310bfe28 100644
--- a/src/calibre/debug.py
+++ b/src/calibre/debug.py
@@ -7,11 +7,14 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 Embedded console for debugging.
 '''
 
-import sys, os, functools
-from calibre.utils.config import OptionParser
-from calibre.constants import iswindows
+import functools
+import os
+import sys
+
 from calibre import prints
+from calibre.constants import iswindows
 from calibre.startup import get_debug_executable
+from calibre.utils.config import OptionParser
 from polyglot.builtins import exec_path
 
 
@@ -132,7 +135,9 @@ def debug_device_driver():
 
 
 def add_simple_plugin(path_to_plugin):
-    import tempfile, zipfile, shutil
+    import shutil
+    import tempfile
+    import zipfile
     tdir = tempfile.mkdtemp()
     open(os.path.join(tdir, 'custom_plugin.py'),
             'wb').write(open(path_to_plugin, 'rb').read())
@@ -152,8 +157,8 @@ def print_basic_debug_info(out=None):
         out = sys.stdout
     out = functools.partial(prints, file=out)
     import platform
-    from calibre.constants import (__appname__, get_version, isportable, ismacos,
-                                   isfrozen)
+
+    from calibre.constants import __appname__, get_version, isfrozen, ismacos, isportable
     from calibre.utils.localization import set_translators
     out(__appname__, get_version(), 'Portable' if isportable else '',
         'embedded-python:', isfrozen)
diff --git a/src/calibre/devices/__init__.py b/src/calibre/devices/__init__.py
index d1427d1ad7..be170ca627 100644
--- a/src/calibre/devices/__init__.py
+++ b/src/calibre/devices/__init__.py
@@ -5,7 +5,9 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 Device drivers.
 '''
 
-import sys, time, pprint
+import pprint
+import sys
+import time
 from functools import partial
 
 DAY_MAP   = dict(Sun=0, Mon=1, Tue=2, Wed=3, Thu=4, Fri=5, Sat=6)
@@ -67,11 +69,12 @@ def debug(ioreg_to_tmp=False, buf=None, plugins=None,
     device plugins as the plugins parameter.
     '''
     import textwrap
+
+    from calibre import prints
+    from calibre.constants import debug, is_debugging, ismacos, iswindows
     from calibre.customize.ui import device_plugins, disabled_device_plugins
     from calibre.debug import print_basic_debug_info
     from calibre.devices.scanner import DeviceScanner
-    from calibre.constants import iswindows, ismacos, debug, is_debugging
-    from calibre import prints
     from polyglot.io import PolyglotStringIO
     oldo, olde = sys.stdout, sys.stderr
 
diff --git a/src/calibre/devices/cli.py b/src/calibre/devices/cli.py
index 1fb276d728..3a3fd2387b 100755
--- a/src/calibre/devices/cli.py
+++ b/src/calibre/devices/cli.py
@@ -9,12 +9,14 @@ Provides a command-line interface to ebook devices.
 For usage information run the script.
 """
 
-import sys, time, os
+import os
+import sys
+import time
 from optparse import OptionParser
 
-from calibre import __version__, __appname__, human_readable, fsync, prints
-from calibre.devices.errors import ArgumentError, DeviceError, DeviceLocked
+from calibre import __appname__, __version__, fsync, human_readable, prints
 from calibre.customize.ui import device_plugins
+from calibre.devices.errors import ArgumentError, DeviceError, DeviceLocked
 from calibre.devices.scanner import DeviceScanner
 from calibre.utils.config import device_prefs
 from polyglot.io import PolyglotStringIO
diff --git a/src/calibre/devices/cybook/driver.py b/src/calibre/devices/cybook/driver.py
index c0e12261d2..61ba5c7018 100644
--- a/src/calibre/devices/cybook/driver.py
+++ b/src/calibre/devices/cybook/driver.py
@@ -9,11 +9,11 @@ Device driver for Bookeen's Cybook Gen 3 and Opus and Orizon
 import os
 import re
 
+import calibre.devices.cybook.t2b as t2b
+import calibre.devices.cybook.t4b as t4b
 from calibre import fsync
 from calibre.constants import isunix
 from calibre.devices.usbms.driver import USBMS
-import calibre.devices.cybook.t2b as t2b
-import calibre.devices.cybook.t4b as t4b
 
 
 class CYBOOK(USBMS):
diff --git a/src/calibre/devices/cybook/t2b.py b/src/calibre/devices/cybook/t2b.py
index 2aab959e2e..aa33eb7577 100644
--- a/src/calibre/devices/cybook/t2b.py
+++ b/src/calibre/devices/cybook/t2b.py
@@ -5,6 +5,7 @@ Write a t2b file to disk.
 '''
 
 import io
+
 from polyglot.builtins import int_to_byte
 
 DEFAULT_T2B_DATA = 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 # noqa
diff --git a/src/calibre/devices/hanvon/driver.py b/src/calibre/devices/hanvon/driver.py
index acb2977b05..e55b3fe80d 100644
--- a/src/calibre/devices/hanvon/driver.py
+++ b/src/calibre/devices/hanvon/driver.py
@@ -5,7 +5,8 @@ __docformat__ = 'restructuredtext en'
 '''
 Device driver for Hanvon devices
 '''
-import re, os
+import os
+import re
 
 from calibre import fsync
 from calibre.devices.usbms.driver import USBMS
diff --git a/src/calibre/devices/kindle/apnx.py b/src/calibre/devices/kindle/apnx.py
index 2f80656f34..8dd285eb01 100644
--- a/src/calibre/devices/kindle/apnx.py
+++ b/src/calibre/devices/kindle/apnx.py
@@ -2,7 +2,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2011, John Schember <john at nachtimwald.com>, refactored: 2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
-from typing import Optional, Dict
+from typing import Dict, Optional
 
 '''
 Generates and writes an APNX page mapping file.
@@ -10,19 +10,18 @@ Generates and writes an APNX page mapping file.
 
 import struct
 
-from calibre.ebooks.pdb.header import PdbHeaderReader
-from calibre.ebooks.mobi.reader.headers import MetadataHeader
-from calibre.utils.logging import default_log
-from calibre import prints, fsync
+from calibre import fsync, prints
 from calibre.constants import DEBUG
-from polyglot.builtins import as_unicode, as_bytes
-
 from calibre.devices.kindle.apnx_page_generator.generators.accurate_page_generator import AccuratePageGenerator
-from calibre.devices.kindle.apnx_page_generator.generators.pagebreak_page_generator import PagebreakPageGenerator
 from calibre.devices.kindle.apnx_page_generator.generators.exact_page_generator import ExactPageGenerator
 from calibre.devices.kindle.apnx_page_generator.generators.fast_page_generator import FastPageGenerator
+from calibre.devices.kindle.apnx_page_generator.generators.pagebreak_page_generator import PagebreakPageGenerator
 from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
+from calibre.ebooks.mobi.reader.headers import MetadataHeader
+from calibre.ebooks.pdb.header import PdbHeaderReader
+from calibre.utils.logging import default_log
+from polyglot.builtins import as_bytes, as_unicode
 
 
 class APNXBuilder:
diff --git a/src/calibre/devices/kindle/apnx_page_generator/generators/pagebreak_page_generator.py b/src/calibre/devices/kindle/apnx_page_generator/generators/pagebreak_page_generator.py
index f80b131556..f9a098f971 100644
--- a/src/calibre/devices/kindle/apnx_page_generator/generators/pagebreak_page_generator.py
+++ b/src/calibre/devices/kindle/apnx_page_generator/generators/pagebreak_page_generator.py
@@ -2,12 +2,12 @@ __license__ = 'GPL v3'
 __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
+import re
 from typing import Optional
 
 from calibre.devices.kindle.apnx_page_generator.generators.fast_page_generator import FastPageGenerator
 from calibre.devices.kindle.apnx_page_generator.i_page_generator import IPageGenerator, mobi_html
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
-import re
 
 
 class PagebreakPageGenerator(IPageGenerator):
diff --git a/src/calibre/devices/kindle/apnx_page_generator/i_page_generator.py b/src/calibre/devices/kindle/apnx_page_generator/i_page_generator.py
index e815c904df..63349edbee 100644
--- a/src/calibre/devices/kindle/apnx_page_generator/i_page_generator.py
+++ b/src/calibre/devices/kindle/apnx_page_generator/i_page_generator.py
@@ -3,13 +3,13 @@ __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
 import struct
-from abc import abstractmethod, ABCMeta
+from abc import ABCMeta, abstractmethod
 from typing import Optional
 
 from calibre.devices.kindle.apnx_page_generator.pages import Pages
+from calibre.ebooks.pdb.header import PdbHeaderReader
 from calibre.utils.logging import default_log
 from polyglot.builtins import as_bytes
-from calibre.ebooks.pdb.header import PdbHeaderReader
 
 
 class IPageGenerator(metaclass=ABCMeta):
diff --git a/src/calibre/devices/kindle/apnx_page_generator/page_group.py b/src/calibre/devices/kindle/apnx_page_generator/page_group.py
index edcf384d3f..9eb8590476 100644
--- a/src/calibre/devices/kindle/apnx_page_generator/page_group.py
+++ b/src/calibre/devices/kindle/apnx_page_generator/page_group.py
@@ -2,7 +2,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
-from typing import Union, List, Tuple
+from typing import List, Tuple, Union
 
 from calibre.devices.kindle.apnx_page_generator.page_number_type import PageNumberTypes
 
diff --git a/src/calibre/devices/kindle/apnx_page_generator/pages.py b/src/calibre/devices/kindle/apnx_page_generator/pages.py
index 6edeeb875a..3588a46304 100644
--- a/src/calibre/devices/kindle/apnx_page_generator/pages.py
+++ b/src/calibre/devices/kindle/apnx_page_generator/pages.py
@@ -3,7 +3,7 @@ __copyright__ = '2022, Vaso Peras-Likodric <vaso at vipl.in.rs>'
 __docformat__ = 'restructuredtext en'
 
 import itertools
-from typing import Optional, List
+from typing import List, Optional
 
 from calibre.devices.kindle.apnx_page_generator.page_group import PageGroup
 from calibre.devices.kindle.apnx_page_generator.page_number_type import PageNumberTypes
diff --git a/src/calibre/devices/kindle/bookmark.py b/src/calibre/devices/kindle/bookmark.py
index 6c2196bd53..b794c963e5 100644
--- a/src/calibre/devices/kindle/bookmark.py
+++ b/src/calibre/devices/kindle/bookmark.py
@@ -1,8 +1,8 @@
 __license__   = 'GPL v3'
 __docformat__ = 'restructuredtext en'
 
-import os
 import io
+import os
 from struct import unpack
 
 
diff --git a/src/calibre/devices/kindle/driver.py b/src/calibre/devices/kindle/driver.py
index 93fa1bd0bf..21bce1ea12 100644
--- a/src/calibre/devices/kindle/driver.py
+++ b/src/calibre/devices/kindle/driver.py
@@ -8,14 +8,18 @@ from calibre.devices.kindle.apnx import APNXBuilder
 Device driver for Amazon's Kindle
 '''
 
-import os, re, json, hashlib, errno
+import errno
+import hashlib
+import json
+import os
+import re
 
+from calibre import fsync, prints, strftime
 from calibre.constants import DEBUG, filesystem_encoding
-from calibre.utils.date import utcfromtimestamp
 from calibre.devices.interface import OpenPopupMessage
 from calibre.devices.kindle.bookmark import Bookmark
 from calibre.devices.usbms.driver import USBMS
-from calibre import strftime, fsync, prints
+from calibre.utils.date import utcfromtimestamp
 from polyglot.builtins import as_bytes, as_unicode
 
 '''
@@ -292,8 +296,8 @@ class KINDLE(USBMS):
         return ka_soup
 
     def add_annotation_to_library(self, db, db_id, annotation):
-        from calibre.ebooks.metadata import MetaInformation
         from calibre.ebooks.BeautifulSoup import prettify
+        from calibre.ebooks.metadata import MetaInformation
 
         bm = annotation
         ignore_tags = {'Catalog', 'Clippings'}
@@ -498,7 +502,7 @@ class KINDLE2(KINDLE):
         return os.path.join(self._main_prefix, 'system', 'thumbnails')
 
     def thumbpath_from_filepath(self, filepath):
-        from calibre.ebooks.metadata.kfx import (CONTAINER_MAGIC, read_book_key_kfx)
+        from calibre.ebooks.metadata.kfx import CONTAINER_MAGIC, read_book_key_kfx
         from calibre.ebooks.mobi.reader.headers import MetadataHeader
         from calibre.utils.logging import default_log
         thumb_dir = self.amazon_system_thumbnails_dir()
diff --git a/src/calibre/devices/kobo/books.py b/src/calibre/devices/kobo/books.py
index 9e450bc845..6fe5e24bba 100644
--- a/src/calibre/devices/kobo/books.py
+++ b/src/calibre/devices/kobo/books.py
@@ -2,17 +2,18 @@ __license__   = 'GPL v3'
 __copyright__ = '2010-2012, , Timothy Legge <timlegge at gmail.com> and David Forrester <davidfor@internode.on.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, time
+import os
+import time
 
-from calibre.constants import preferred_encoding, DEBUG
 from calibre import isbytestring
-
-from calibre.ebooks.metadata.book.base import Metadata
-from calibre.ebooks.metadata.book.formatter import SafeFormat
-from calibre.devices.usbms.books import Book as Book_, CollectionsBookList
-from calibre.utils.config_base import prefs
+from calibre.constants import DEBUG, preferred_encoding
+from calibre.devices.usbms.books import Book as Book_
+from calibre.devices.usbms.books import CollectionsBookList
 from calibre.devices.usbms.driver import debug_print
 from calibre.ebooks.metadata import author_to_author_sort
+from calibre.ebooks.metadata.book.base import Metadata
+from calibre.ebooks.metadata.book.formatter import SafeFormat
+from calibre.utils.config_base import prefs
 
 
 class Book(Book_):
diff --git a/src/calibre/devices/kobo/driver.py b/src/calibre/devices/kobo/driver.py
index 0dff8de229..94f3001256 100644
--- a/src/calibre/devices/kobo/driver.py
+++ b/src/calibre/devices/kobo/driver.py
@@ -13,26 +13,25 @@ Extended to support Touch firmware 2.0.0 and later and newer devices by David Fo
 Additional maintenance performed by Peter Thomas <peterjt@gmail.com>
 '''
 
-import os, time, shutil, re
-
+import os
+import re
+import shutil
+import time
 from contextlib import closing
 from datetime import datetime
-from calibre import strftime
-from calibre.utils.date import parse_date
-from calibre.devices.usbms.books import BookList
-from calibre.devices.usbms.books import CollectionsBookList
-from calibre.devices.kobo.books import KTCollectionsBookList
+
+from calibre import fsync, prints, strftime
+from calibre.constants import DEBUG
+from calibre.devices.kobo.books import Book, ImageWrapper, KTCollectionsBookList
+from calibre.devices.mime import mime_type_ext
+from calibre.devices.usbms.books import BookList, CollectionsBookList
+from calibre.devices.usbms.driver import USBMS, debug_print
 from calibre.ebooks.metadata import authors_to_string
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.utils import normalize_languages
-from calibre.devices.kobo.books import Book
-from calibre.devices.kobo.books import ImageWrapper
-from calibre.devices.mime import mime_type_ext
-from calibre.devices.usbms.driver import USBMS, debug_print
-from calibre import prints, fsync
 from calibre.ptempfile import PersistentTemporaryFile, better_mktemp
-from calibre.constants import DEBUG
 from calibre.utils.config_base import prefs
+from calibre.utils.date import parse_date
 from polyglot.builtins import iteritems, itervalues, string_or_bytes
 
 EPUB_EXT  = '.epub'
@@ -1231,6 +1230,7 @@ class KOBO(USBMS):
 
     def generate_annotation_html(self, bookmark):
         import calendar
+
         from calibre.ebooks.BeautifulSoup import BeautifulSoup
         # Returns <div class="user_annotations"> ... </div>
         # last_read_location = bookmark.last_read_location
@@ -2795,8 +2795,8 @@ class KOBOTOUCH(KOBO):
             dithered_covers=False, keep_cover_aspect=False, letterbox_fs_covers=False, png_covers=False,
             letterbox_color=DEFAULT_COVER_LETTERBOX_COLOR
             ):
-        from calibre.utils.imghdr import identify
         from calibre.utils.img import optimize_png
+        from calibre.utils.imghdr import identify
         debug_print("KoboTouch:_upload_cover - filename='%s' upload_grayscale='%s' dithered_covers='%s' "%(filename, upload_grayscale, dithered_covers))
 
         if not metadata.cover:
diff --git a/src/calibre/devices/kobo/kobotouch_config.py b/src/calibre/devices/kobo/kobotouch_config.py
index a65eb5c815..878ad70e46 100644
--- a/src/calibre/devices/kobo/kobotouch_config.py
+++ b/src/calibre/devices/kobo/kobotouch_config.py
@@ -6,15 +6,14 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from qt.core import (QWidget, QLabel, QGridLayout, QLineEdit, QVBoxLayout, QDialog,
-                     QDialogButtonBox, QCheckBox, QPushButton)
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QLabel, QLineEdit, QPushButton, QVBoxLayout, QWidget
 
-from calibre.gui2.device_drivers.tabbed_device_config import TabbedDeviceConfig, DeviceConfigTab, DeviceOptionsGroupBox
 from calibre.devices.usbms.driver import debug_print
 from calibre.gui2 import error_dialog
-from calibre.gui2.widgets2 import ColorButton
+from calibre.gui2.device_drivers.tabbed_device_config import DeviceConfigTab, DeviceOptionsGroupBox, TabbedDeviceConfig
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
 from calibre.gui2.dialogs.template_line_editor import TemplateLineEditor
+from calibre.gui2.widgets2 import ColorButton
 
 
 def wrap_msg(msg):
@@ -808,9 +807,9 @@ class TemplateConfig(QWidget):  # {{{
 
 
 if __name__ == '__main__':
-    from calibre.gui2 import Application
     from calibre.devices.kobo.driver import KOBOTOUCH
     from calibre.devices.scanner import DeviceScanner
+    from calibre.gui2 import Application
     s = DeviceScanner()
     s.scan()
     app = Application([])
diff --git a/src/calibre/devices/misc.py b/src/calibre/devices/misc.py
index 4cd63e2d1e..770cb39fc5 100644
--- a/src/calibre/devices/misc.py
+++ b/src/calibre/devices/misc.py
@@ -7,8 +7,8 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.devices.usbms.driver import USBMS
 from calibre import fsync
+from calibre.devices.usbms.driver import USBMS
 
 
 class PALMPRE(USBMS):
diff --git a/src/calibre/devices/mtp/defaults.py b/src/calibre/devices/mtp/defaults.py
index 274e5ca4d7..db3c9400e0 100644
--- a/src/calibre/devices/mtp/defaults.py
+++ b/src/calibre/devices/mtp/defaults.py
@@ -5,12 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import traceback, re
+import re
+import traceback
 
 from calibre.constants import iswindows
 from polyglot.builtins import iteritems
 
-
 supernote_settings = {
     'calibre_file_paths': {'metadata':'Document/metadata.calibre', 'driveinfo':'Document/driveinfo.calibre'},
     'send_to': ['Document', 'Documents'],
diff --git a/src/calibre/devices/mtp/filesystem_cache.py b/src/calibre/devices/mtp/filesystem_cache.py
index 14b031bc6b..bdac9e14a0 100644
--- a/src/calibre/devices/mtp/filesystem_cache.py
+++ b/src/calibre/devices/mtp/filesystem_cache.py
@@ -5,16 +5,18 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import weakref, sys, json
+import json
+import sys
+import weakref
 from collections import deque
-from operator import attrgetter
-from polyglot.builtins import itervalues
 from datetime import datetime
+from operator import attrgetter
 
-from calibre import human_readable, prints, force_unicode
-from calibre.utils.date import local_tz, as_utc
-from calibre.utils.icu import sort_key, lower
+from calibre import force_unicode, human_readable, prints
 from calibre.ebooks import BOOK_EXTENSIONS
+from calibre.utils.date import as_utc, local_tz
+from calibre.utils.icu import lower, sort_key
+from polyglot.builtins import itervalues
 
 bexts = frozenset(BOOK_EXTENSIONS) - {'mbp', 'tan', 'rar', 'zip', 'xml'}
 
diff --git a/src/calibre/devices/mtp/test.py b/src/calibre/devices/mtp/test.py
index 5e62e3ceb5..4fe57e6bd7 100644
--- a/src/calibre/devices/mtp/test.py
+++ b/src/calibre/devices/mtp/test.py
@@ -5,12 +5,14 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import unittest, gc, io
+import gc
+import io
+import unittest
 
-from calibre.constants import iswindows, islinux
-from calibre.utils.icu import lower
+from calibre.constants import islinux, iswindows
 from calibre.devices.mtp.driver import MTP_DEVICE
 from calibre.devices.scanner import DeviceScanner
+from calibre.utils.icu import lower
 
 
 class ProgressCallback:
diff --git a/src/calibre/devices/mtp/unix/driver.py b/src/calibre/devices/mtp/unix/driver.py
index 611879e1b7..d3ea7b7490 100644
--- a/src/calibre/devices/mtp/unix/driver.py
+++ b/src/calibre/devices/mtp/unix/driver.py
@@ -4,16 +4,20 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import operator, traceback, pprint, sys, time
-from threading import RLock
+import operator
+import pprint
+import sys
+import time
+import traceback
 from collections import namedtuple
 from functools import partial
+from threading import RLock
 
-from calibre import prints, as_unicode, force_unicode
+from calibre import as_unicode, force_unicode, prints
 from calibre.constants import islinux, ismacos
+from calibre.devices.errors import BlacklistedDevice, DeviceError, OpenActionNeeded, OpenFailed
+from calibre.devices.mtp.base import MTPDeviceBase, debug, synchronous
 from calibre.ptempfile import SpooledTemporaryFile
-from calibre.devices.errors import OpenFailed, DeviceError, BlacklistedDevice, OpenActionNeeded
-from calibre.devices.mtp.base import MTPDeviceBase, synchronous, debug
 
 MTPDevice = namedtuple('MTPDevice', 'busnum devnum vendor_id product_id '
         'bcd serial manufacturer product')
diff --git a/src/calibre/devices/mtp/unix/sysfs.py b/src/calibre/devices/mtp/unix/sysfs.py
index 95159069ea..12f3c1299c 100644
--- a/src/calibre/devices/mtp/unix/sysfs.py
+++ b/src/calibre/devices/mtp/unix/sysfs.py
@@ -5,7 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, glob
+import glob
+import os
 
 
 class MTPDetect:
diff --git a/src/calibre/devices/mtp/unix/upstream/update.py b/src/calibre/devices/mtp/unix/upstream/update.py
index c43d90cbc8..ae32f3e75d 100755
--- a/src/calibre/devices/mtp/unix/upstream/update.py
+++ b/src/calibre/devices/mtp/unix/upstream/update.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, shutil, subprocess
+import os
+import shutil
+import subprocess
 
 base = os.path.dirname(os.path.abspath(__file__))
 
diff --git a/src/calibre/devices/mtp/windows/driver.py b/src/calibre/devices/mtp/windows/driver.py
index a30fd0d17f..b83df4d653 100644
--- a/src/calibre/devices/mtp/windows/driver.py
+++ b/src/calibre/devices/mtp/windows/driver.py
@@ -5,16 +5,18 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import time, threading, traceback
-from functools import wraps, partial
-from polyglot.builtins import iteritems, itervalues
+import threading
+import time
+import traceback
+from functools import partial, wraps
 from itertools import chain
 
-from calibre import as_unicode, prints, force_unicode
-from calibre.constants import __appname__, numeric_version, isxp
-from calibre.ptempfile import SpooledTemporaryFile
-from calibre.devices.errors import OpenFailed, DeviceError, BlacklistedDevice
+from calibre import as_unicode, force_unicode, prints
+from calibre.constants import __appname__, isxp, numeric_version
+from calibre.devices.errors import BlacklistedDevice, DeviceError, OpenFailed
 from calibre.devices.mtp.base import MTPDeviceBase, debug
+from calibre.ptempfile import SpooledTemporaryFile
+from polyglot.builtins import iteritems, itervalues
 
 null = object()
 
diff --git a/src/calibre/devices/paladin/driver.py b/src/calibre/devices/paladin/driver.py
index 1ddec6b72c..30f610a787 100644
--- a/src/calibre/devices/paladin/driver.py
+++ b/src/calibre/devices/paladin/driver.py
@@ -6,13 +6,15 @@
 Device driver for the Paladin devices
 '''
 
-import os, time, sys
+import os
+import sys
+import time
 from contextlib import closing
 
-from calibre.devices.mime import mime_type_ext
 from calibre.devices.errors import DeviceError
+from calibre.devices.mime import mime_type_ext
+from calibre.devices.usbms.books import BookList, CollectionsBookList
 from calibre.devices.usbms.driver import USBMS, debug_print
-from calibre.devices.usbms.books import CollectionsBookList, BookList
 
 DBPATH = 'paladin/database/books.db'
 
@@ -306,8 +308,8 @@ class PALADIN(USBMS):
 
     def update_device_books(self, connection, booklist, source_id, plugboard,
             dbpath):
-        from calibre.ebooks.metadata.meta import path_to_ext
         from calibre.ebooks.metadata import authors_to_sort_string, authors_to_string
+        from calibre.ebooks.metadata.meta import path_to_ext
         opts = self.settings()
 
         db_books = self.read_device_books(connection, source_id, dbpath)
diff --git a/src/calibre/devices/prs505/driver.py b/src/calibre/devices/prs505/driver.py
index 8ae6ee8922..dffda59e58 100644
--- a/src/calibre/devices/prs505/driver.py
+++ b/src/calibre/devices/prs505/driver.py
@@ -6,14 +6,14 @@ __docformat__ = 'restructuredtext en'
 Device driver for the SONY devices
 '''
 
-import os, time, re
+import os
+import re
+import time
 
-from calibre import fsync
-from calibre.devices.usbms.driver import USBMS, debug_print
-from calibre.devices.prs505 import MEDIA_XML, MEDIA_EXT, CACHE_XML, CACHE_EXT, \
-            MEDIA_THUMBNAIL, CACHE_THUMBNAIL
-from calibre import __appname__, prints
+from calibre import __appname__, fsync, prints
+from calibre.devices.prs505 import CACHE_EXT, CACHE_THUMBNAIL, CACHE_XML, MEDIA_EXT, MEDIA_THUMBNAIL, MEDIA_XML
 from calibre.devices.usbms.books import CollectionsBookList
+from calibre.devices.usbms.driver import USBMS, debug_print
 
 
 class PRS505(USBMS):
diff --git a/src/calibre/devices/prs505/sony_cache.py b/src/calibre/devices/prs505/sony_cache.py
index c40de0dc46..71462e3b2a 100644
--- a/src/calibre/devices/prs505/sony_cache.py
+++ b/src/calibre/devices/prs505/sony_cache.py
@@ -5,16 +5,16 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, time
+import os
+import time
 from datetime import date
 
-from calibre import prints, guess_type, isbytestring, fsync
+from calibre import fsync, guess_type, isbytestring, prints
+from calibre.constants import DEBUG, preferred_encoding
 from calibre.devices.errors import DeviceError
 from calibre.devices.usbms.driver import debug_print
-from calibre.constants import DEBUG, preferred_encoding
 from calibre.ebooks.chardet import xml_to_unicode
-from calibre.ebooks.metadata import authors_to_string, title_sort, \
-                                    authors_to_sort_string
+from calibre.ebooks.metadata import authors_to_sort_string, authors_to_string, title_sort
 from polyglot.binary import from_base64_bytes
 
 '''
diff --git a/src/calibre/devices/prst1/driver.py b/src/calibre/devices/prst1/driver.py
index 0c74864763..6a30657da3 100644
--- a/src/calibre/devices/prst1/driver.py
+++ b/src/calibre/devices/prst1/driver.py
@@ -9,19 +9,20 @@ __docformat__ = 'restructuredtext en'
 Device driver for the SONY T1 devices
 '''
 
-import os, time, re
+import os
+import re
+import time
 from contextlib import closing
 from datetime import date
 
 from calibre import fsync
-from calibre.devices.mime import mime_type_ext
-from calibre.devices.errors import DeviceError
-from calibre.devices.usbms.driver import USBMS, debug_print
-from calibre.devices.usbms.device import USBDevice
-from calibre.devices.usbms.books import CollectionsBookList
-from calibre.devices.usbms.books import BookList
-from calibre.ebooks.metadata import authors_to_sort_string, authors_to_string
 from calibre.constants import islinux
+from calibre.devices.errors import DeviceError
+from calibre.devices.mime import mime_type_ext
+from calibre.devices.usbms.books import BookList, CollectionsBookList
+from calibre.devices.usbms.device import USBDevice
+from calibre.devices.usbms.driver import USBMS, debug_print
+from calibre.ebooks.metadata import authors_to_sort_string, authors_to_string
 from polyglot.builtins import long_type
 
 DBPATH = 'Sony_Reader/database/books.db'
diff --git a/src/calibre/devices/scanner.py b/src/calibre/devices/scanner.py
index b8f340a893..3191b69052 100644
--- a/src/calibre/devices/scanner.py
+++ b/src/calibre/devices/scanner.py
@@ -5,13 +5,14 @@ Device scanner that fetches list of devices on system ina  platform dependent
 manner.
 '''
 
-import sys, os, time
+import os
+import sys
+import time
 from collections import namedtuple
 from threading import Lock
 
-from calibre import prints, as_unicode
-from calibre.constants import (iswindows, ismacos, islinux, isfreebsd,
-        isnetbsd)
+from calibre import as_unicode, prints
+from calibre.constants import isfreebsd, islinux, ismacos, isnetbsd, iswindows
 
 osx_scanner = linux_scanner = freebsd_scanner = netbsd_scanner = None
 
@@ -79,6 +80,7 @@ class LibUSBScanner:
 
     def check_for_mem_leak(self):
         import gc
+
         from calibre.utils.mem import memory
         memory()
         for num in (1, 10, 100):
@@ -199,8 +201,9 @@ class DeviceScanner:
 
 
 def test_for_mem_leak():
-    from calibre.utils.mem import memory, gc_histogram, diff_hists
     import gc
+
+    from calibre.utils.mem import diff_hists, gc_histogram, memory
     gc.disable()
     scanner = DeviceScanner()
     scanner.scan()
diff --git a/src/calibre/devices/smart_device_app/driver.py b/src/calibre/devices/smart_device_app/driver.py
index 170ddb896d..f512914853 100644
--- a/src/calibre/devices/smart_device_app/driver.py
+++ b/src/calibre/devices/smart_device_app/driver.py
@@ -23,10 +23,7 @@ from threading import Thread
 
 from calibre import prints
 from calibre.constants import DEBUG, cache_dir, numeric_version
-from calibre.devices.errors import (
-    ControlError, InitialConnectionError, OpenFailed, OpenFeedback, PacketError,
-    TimeoutError, UserFeedback
-)
+from calibre.devices.errors import ControlError, InitialConnectionError, OpenFailed, OpenFeedback, PacketError, TimeoutError, UserFeedback
 from calibre.devices.interface import DevicePlugin, currently_connected_device
 from calibre.devices.usbms.books import Book, CollectionsBookList
 from calibre.devices.usbms.deviceconfig import DeviceConfig
@@ -39,11 +36,12 @@ from calibre.ebooks.metadata.book.json_codec import JsonCodec
 from calibre.library import current_library_name
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.utils.config_base import tweaks
-from calibre.utils.filenames import ascii_filename as sanitize, shorten_components_to
+from calibre.utils.filenames import ascii_filename as sanitize
+from calibre.utils.filenames import shorten_components_to
 from calibre.utils.ipc import eintr_retry_call
-from calibre.utils.mdns import (
-    get_all_ips, publish as publish_zeroconf, unpublish as unpublish_zeroconf
-)
+from calibre.utils.mdns import get_all_ips
+from calibre.utils.mdns import publish as publish_zeroconf
+from calibre.utils.mdns import unpublish as unpublish_zeroconf
 from calibre.utils.socket_inheritance import set_socket_inherit
 from polyglot import queue
 from polyglot.builtins import as_bytes, iteritems, itervalues
diff --git a/src/calibre/devices/usbms/books.py b/src/calibre/devices/usbms/books.py
index 173475f8ee..4092d7d991 100644
--- a/src/calibre/devices/usbms/books.py
+++ b/src/calibre/devices/usbms/books.py
@@ -2,18 +2,21 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-import os, re, time, sys
+import os
+import re
+import sys
+import time
 from functools import cmp_to_key
 
+from calibre import force_unicode, isbytestring
+from calibre.constants import preferred_encoding
+from calibre.devices.interface import BookList as _BookList
+from calibre.devices.mime import mime_type_ext
 from calibre.ebooks.metadata import title_sort
 from calibre.ebooks.metadata.book.base import Metadata
-from calibre.devices.mime import mime_type_ext
-from calibre.devices.interface import BookList as _BookList
-from calibre.constants import preferred_encoding
-from calibre import isbytestring, force_unicode
 from calibre.utils.config_base import tweaks
 from calibre.utils.icu import sort_key
-from polyglot.builtins import string_or_bytes, iteritems, itervalues, cmp
+from polyglot.builtins import cmp, iteritems, itervalues, string_or_bytes
 
 
 def none_cmp(xx, yy):
diff --git a/src/calibre/devices/usbms/cli.py b/src/calibre/devices/usbms/cli.py
index 6ad4ce6592..d1d1571167 100644
--- a/src/calibre/devices/usbms/cli.py
+++ b/src/calibre/devices/usbms/cli.py
@@ -2,7 +2,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-import os, shutil, time
+import os
+import shutil
+import time
 
 from calibre import fsync
 from calibre.devices.errors import PathError
diff --git a/src/calibre/devices/usbms/driver.py b/src/calibre/devices/usbms/driver.py
index c398aaad8c..db09fbd8b3 100644
--- a/src/calibre/devices/usbms/driver.py
+++ b/src/calibre/devices/usbms/driver.py
@@ -8,15 +8,17 @@ driver. It is intended to be subclassed with the relevant parts implemented
 for a particular device.
 '''
 
-import os, time, json, shutil
+import json
+import os
+import shutil
+import time
 from itertools import cycle
 
-from calibre.constants import numeric_version, ismacos
-from calibre import prints, isbytestring, fsync
-from calibre.constants import filesystem_encoding, is_debugging
+from calibre import fsync, isbytestring, prints
+from calibre.constants import filesystem_encoding, is_debugging, ismacos, numeric_version
+from calibre.devices.usbms.books import Book, BookList
 from calibre.devices.usbms.cli import CLI
 from calibre.devices.usbms.device import Device
-from calibre.devices.usbms.books import BookList, Book
 from calibre.ebooks.metadata.book.json_codec import JsonCodec
 from polyglot.builtins import itervalues, string_or_bytes
 
@@ -98,8 +100,9 @@ class USBMS(CLI, Device):
     SCAN_FROM_ROOT = False
 
     def _update_driveinfo_record(self, dinfo, prefix, location_code, name=None):
-        from calibre.utils.date import now, isoformat
         import uuid
+
+        from calibre.utils.date import isoformat, now
         if not isinstance(dinfo, dict):
             dinfo = {}
         if dinfo.get('device_store_uuid', None) is None:
@@ -537,8 +540,8 @@ class USBMS(CLI, Device):
 
     @classmethod
     def metadata_from_formats(cls, fmts):
-        from calibre.ebooks.metadata.meta import metadata_from_formats
         from calibre.customize.ui import quick_metadata
+        from calibre.ebooks.metadata.meta import metadata_from_formats
         with quick_metadata:
             return metadata_from_formats(fmts, force_read_metadata=True,
                                          pattern=cls.build_template_regexp())
diff --git a/src/calibre/devices/usbms/hal.py b/src/calibre/devices/usbms/hal.py
index 1478f3b904..898206add1 100644
--- a/src/calibre/devices/usbms/hal.py
+++ b/src/calibre/devices/usbms/hal.py
@@ -2,10 +2,10 @@
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 import time
-from jeepney import (
-    DBusAddress, DBusErrorResponse, MessageType, Properties, new_method_call
-)
+
+from jeepney import DBusAddress, DBusErrorResponse, MessageType, Properties, new_method_call
 from jeepney.io.blocking import open_dbus_connection
+
 from calibre.constants import DEBUG
 
 
diff --git a/src/calibre/devices/utils.py b/src/calibre/devices/utils.py
index 77f31cfa8b..071c3be9b6 100644
--- a/src/calibre/devices/utils.py
+++ b/src/calibre/devices/utils.py
@@ -5,10 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, time, re
+import os
+import re
+import time
 from functools import partial
 
-from calibre.devices.errors import DeviceError, WrongDestinationError, FreeSpaceError
+from calibre.devices.errors import DeviceError, FreeSpaceError, WrongDestinationError
 
 
 def sanity_check(on_card, files, card_prefixes, free_space):
@@ -72,7 +74,7 @@ def create_upload_path(mdata, fname, template, sanitize,
         filename_callback=lambda x, y:x,
         sanitize_path_components=lambda x: x
         ):
-    from calibre.library.save_to_disk import get_components, config
+    from calibre.library.save_to_disk import config, get_components
     from calibre.utils.filenames import shorten_components_to
 
     special_tag = None
diff --git a/src/calibre/devices/winusb.py b/src/calibre/devices/winusb.py
index ecb16d3097..9e453bf3dd 100644
--- a/src/calibre/devices/winusb.py
+++ b/src/calibre/devices/winusb.py
@@ -2,19 +2,39 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import os, string, re, errno
-from collections import namedtuple, defaultdict
-from operator import itemgetter
+import errno
+import os
+import re
+import string
+from collections import defaultdict, namedtuple
 from ctypes import (
-    Structure, POINTER, c_ubyte, windll, byref, c_void_p, WINFUNCTYPE, c_uint,
-    WinError, get_last_error, sizeof, c_wchar, create_string_buffer, cast,
-    memset, wstring_at, addressof, create_unicode_buffer, string_at, c_uint64 as QWORD
+    POINTER,
+    WINFUNCTYPE,
+    Structure,
+    WinError,
+    addressof,
+    byref,
+    c_ubyte,
+    c_uint,
+    c_void_p,
+    c_wchar,
+    cast,
+    create_string_buffer,
+    create_unicode_buffer,
+    get_last_error,
+    memset,
+    sizeof,
+    string_at,
+    windll,
+    wstring_at,
 )
-from ctypes.wintypes import DWORD, WORD, ULONG, LPCWSTR, HWND, BOOL, LPWSTR, UINT, BYTE, HANDLE, USHORT
-from pprint import pprint, pformat
-from polyglot.builtins import iteritems, itervalues
+from ctypes import c_uint64 as QWORD
+from ctypes.wintypes import BOOL, BYTE, DWORD, HANDLE, HWND, LPCWSTR, LPWSTR, UINT, ULONG, USHORT, WORD
+from operator import itemgetter
+from pprint import pformat, pprint
 
-from calibre import prints, as_unicode
+from calibre import as_unicode, prints
+from polyglot.builtins import iteritems, itervalues
 
 try:
     import winreg
diff --git a/src/calibre/ebooks/BeautifulSoup.py b/src/calibre/ebooks/BeautifulSoup.py
index c4f7e1a24d..8f9d951f73 100644
--- a/src/calibre/ebooks/BeautifulSoup.py
+++ b/src/calibre/ebooks/BeautifulSoup.py
@@ -3,14 +3,11 @@
 
 
 import bs4
-from bs4 import (  # noqa
-    CData, Comment, Declaration, NavigableString, ProcessingInstruction,
-    SoupStrainer, Tag, __version__
-)
+from bs4 import CData, Comment, Declaration, NavigableString, ProcessingInstruction, SoupStrainer, Tag, __version__  # noqa
 
 
 def parse_html(markup):
-    from calibre.ebooks.chardet import strip_encoding_declarations, xml_to_unicode, substitute_entites
+    from calibre.ebooks.chardet import strip_encoding_declarations, substitute_entites, xml_to_unicode
     from calibre.utils.cleantext import clean_xml_chars
     if isinstance(markup, str):
         markup = strip_encoding_declarations(markup)
diff --git a/src/calibre/ebooks/chardet.py b/src/calibre/ebooks/chardet.py
index 01bc822dda..52f4824528 100644
--- a/src/calibre/ebooks/chardet.py
+++ b/src/calibre/ebooks/chardet.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, codecs, sys
+import codecs
+import re
+import sys
 
 _encoding_pats = (
     # XML declaration
diff --git a/src/calibre/ebooks/chm/metadata.py b/src/calibre/ebooks/chm/metadata.py
index 502a5a0f96..18736d2ecc 100644
--- a/src/calibre/ebooks/chm/metadata.py
+++ b/src/calibre/ebooks/chm/metadata.py
@@ -5,14 +5,15 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, codecs
+import codecs
+import re
 
+from calibre import force_unicode
 from calibre.ebooks.BeautifulSoup import BeautifulSoup
 from calibre.ebooks.chardet import xml_to_unicode
-from calibre.ebooks.metadata import string_to_authors, MetaInformation
-from calibre.utils.logging import default_log
+from calibre.ebooks.metadata import MetaInformation, string_to_authors
 from calibre.ptempfile import TemporaryFile
-from calibre import force_unicode
+from calibre.utils.logging import default_log
 from polyglot.builtins import iterkeys
 
 
@@ -124,8 +125,9 @@ def _get_cover(soup, rdr):
             except:
                 ans = None
         if ans is not None:
-            from PIL import Image
             import io
+
+            from PIL import Image
             buf = io.BytesIO()
             try:
                 Image.open(io.BytesIO(ans)).convert('RGB').save(buf, 'JPEG')
diff --git a/src/calibre/ebooks/chm/reader.py b/src/calibre/ebooks/chm/reader.py
index 7da8e4efe6..9bdd1a1c99 100644
--- a/src/calibre/ebooks/chm/reader.py
+++ b/src/calibre/ebooks/chm/reader.py
@@ -7,6 +7,7 @@ import codecs
 import os
 import re
 import struct
+
 from chm.chm import CHMFile, chmlib
 
 from calibre import guess_type as guess_mimetype
diff --git a/src/calibre/ebooks/comic/input.py b/src/calibre/ebooks/comic/input.py
index 87c7832f05..76951d0883 100644
--- a/src/calibre/ebooks/comic/input.py
+++ b/src/calibre/ebooks/comic/input.py
@@ -114,8 +114,8 @@ class PageProcessor(list):  # {{{
     def render(self):
         from qt.core import QImage
 
-        from calibre.utils.img import crop_image, image_from_data, scale_image
         from calibre.utils.filenames import make_long_path_useable
+        from calibre.utils.img import crop_image, image_from_data, scale_image
         with open(make_long_path_useable(self.path_to_page), 'rb') as f:
             img = image_from_data(f.read())
         width, height = img.width(), img.height()
@@ -140,9 +140,15 @@ class PageProcessor(list):  # {{{
         from qt.core import QImage
 
         from calibre.utils.img import (
-            add_borders_to_image, despeckle_image, gaussian_sharpen_image,
-            image_to_data, normalize_image, quantize_image, remove_borders_from_image,
-            resize_image, rotate_image,
+            add_borders_to_image,
+            despeckle_image,
+            gaussian_sharpen_image,
+            image_to_data,
+            normalize_image,
+            quantize_image,
+            remove_borders_from_image,
+            resize_image,
+            rotate_image,
         )
         for i, img in enumerate(self.pages):
             if self.rotate:
diff --git a/src/calibre/ebooks/compression/tcr.py b/src/calibre/ebooks/compression/tcr.py
index aa72bec8a9..76e63e958e 100644
--- a/src/calibre/ebooks/compression/tcr.py
+++ b/src/calibre/ebooks/compression/tcr.py
@@ -3,6 +3,7 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 import re
+
 from polyglot.builtins import int_to_byte
 
 
diff --git a/src/calibre/ebooks/conversion/cli.py b/src/calibre/ebooks/conversion/cli.py
index b7c5cdfd7b..3a9d18ed60 100644
--- a/src/calibre/ebooks/conversion/cli.py
+++ b/src/calibre/ebooks/conversion/cli.py
@@ -6,16 +6,18 @@ __docformat__ = 'restructuredtext en'
 Command line interface to conversion sub-system
 '''
 
-import sys, os, numbers
-from optparse import OptionGroup, Option
+import numbers
+import os
+import sys
 from collections import OrderedDict
+from optparse import Option, OptionGroup
 
-from calibre.utils.config import OptionParser
-from calibre.utils.logging import Log
-from calibre.customize.conversion import OptionRecommendation
 from calibre import patheq
+from calibre.customize.conversion import OptionRecommendation
 from calibre.ebooks.conversion import ConversionUserFeedBack
+from calibre.utils.config import OptionParser
 from calibre.utils.localization import localize_user_manual_link
+from calibre.utils.logging import Log
 from polyglot.builtins import iteritems
 
 USAGE = '%prog ' + _('''\
@@ -297,7 +299,7 @@ class ProgressBar:
 
 def create_option_parser(args, log):
     if '--version' in args:
-        from calibre.constants import __appname__, __version__, __author__
+        from calibre.constants import __appname__, __author__, __version__
         log(os.path.basename(args[0]), '('+__appname__, __version__+')')
         log('Created by:', __author__)
         raise SystemExit(0)
@@ -347,7 +349,8 @@ def escape_sr_pattern(exp):
 
 
 def read_sr_patterns(path, log=None):
-    import json, re
+    import json
+    import re
     pats = []
     with open(path, 'rb') as f:
         lines = f.read().decode('utf-8').splitlines()
diff --git a/src/calibre/ebooks/conversion/config.py b/src/calibre/ebooks/conversion/config.py
index 6ce9ad52a5..0fff29dea5 100644
--- a/src/calibre/ebooks/conversion/config.py
+++ b/src/calibre/ebooks/conversion/config.py
@@ -5,14 +5,15 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, ast, json
+import ast
+import json
+import os
 
-from calibre.utils.config import config_dir, prefs, tweaks
-from calibre.utils.lock import ExclusiveFile
 from calibre import sanitize_file_name
 from calibre.customize.conversion import OptionRecommendation
 from calibre.customize.ui import available_output_formats
-
+from calibre.utils.config import config_dir, prefs, tweaks
+from calibre.utils.lock import ExclusiveFile
 
 config_dir = os.path.join(config_dir, 'conversion')
 
diff --git a/src/calibre/ebooks/conversion/plugins/azw4_input.py b/src/calibre/ebooks/conversion/plugins/azw4_input.py
index 0658b01d10..95a1db72d8 100644
--- a/src/calibre/ebooks/conversion/plugins/azw4_input.py
+++ b/src/calibre/ebooks/conversion/plugins/azw4_input.py
@@ -17,8 +17,8 @@ class AZW4Input(InputFormatPlugin):
 
     def convert(self, stream, options, file_ext, log,
                 accelerators):
-        from calibre.ebooks.pdb.header import PdbHeaderReader
         from calibre.ebooks.azw4.reader import Reader
+        from calibre.ebooks.pdb.header import PdbHeaderReader
 
         header = PdbHeaderReader(stream)
         reader = Reader(header, stream, log, options)
diff --git a/src/calibre/ebooks/conversion/plugins/chm_input.py b/src/calibre/ebooks/conversion/plugins/chm_input.py
index ce42ebcaa6..4fc30bf8de 100644
--- a/src/calibre/ebooks/conversion/plugins/chm_input.py
+++ b/src/calibre/ebooks/conversion/plugins/chm_input.py
@@ -5,9 +5,9 @@ __copyright__  = '2008, Kovid Goyal <kovid at kovidgoyal.net>,' \
 
 import os
 
+from calibre.constants import filesystem_encoding
 from calibre.customize.conversion import InputFormatPlugin
 from calibre.ptempfile import TemporaryDirectory
-from calibre.constants import filesystem_encoding
 from polyglot.builtins import as_bytes
 
 
@@ -29,8 +29,8 @@ class CHMInput(InputFormatPlugin):
         return rdr.hhc_path
 
     def convert(self, stream, options, file_ext, log, accelerators):
-        from calibre.ebooks.chm.metadata import get_metadata_from_reader
         from calibre.customize.ui import plugin_for_input_format
+        from calibre.ebooks.chm.metadata import get_metadata_from_reader
         self.opts = options
 
         log.debug('Processing CHM...')
@@ -112,9 +112,10 @@ class CHMInput(InputFormatPlugin):
 
     def _create_html_root(self, hhcpath, log, encoding):
         from lxml import html
-        from polyglot.urllib import unquote as _unquote
-        from calibre.ebooks.oeb.base import urlquote
+
         from calibre.ebooks.chardet import xml_to_unicode
+        from calibre.ebooks.oeb.base import urlquote
+        from polyglot.urllib import unquote as _unquote
         try:
             hhcdata = self._read_file(hhcpath)
         except FileNotFoundError:
@@ -170,7 +171,7 @@ class CHMInput(InputFormatPlugin):
 
         with open(htmlpath, 'wb') as f:
             if toc.count() > 1:
-                from lxml.html.builder import HTML, BODY, DIV, A
+                from lxml.html.builder import BODY, DIV, HTML, A
                 path0 = toc[0].href
                 path0 = unquote_path(path0)[0]
                 subpath = os.path.dirname(path0)
diff --git a/src/calibre/ebooks/conversion/plugins/docx_output.py b/src/calibre/ebooks/conversion/plugins/docx_output.py
index 7ed0ccff6d..0cf5ddcbb0 100644
--- a/src/calibre/ebooks/conversion/plugins/docx_output.py
+++ b/src/calibre/ebooks/conversion/plugins/docx_output.py
@@ -4,7 +4,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from calibre.customize.conversion import OutputFormatPlugin, OptionRecommendation
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 
 PAGE_SIZES = ['a0', 'a1', 'a2', 'a3', 'a4', 'a5', 'a6', 'b0', 'b1',
               'b2', 'b3', 'b4', 'b5', 'b6', 'legal', 'letter']
@@ -72,10 +72,12 @@ class DOCXOutput(OutputFormatPlugin):
     }
 
     def convert_metadata(self, oeb):
-        from lxml import etree
-        from calibre.ebooks.oeb.base import OPF, OPF2_NS
-        from calibre.ebooks.metadata.opf2 import OPF as ReadOPF
         from io import BytesIO
+
+        from lxml import etree
+
+        from calibre.ebooks.metadata.opf2 import OPF as ReadOPF
+        from calibre.ebooks.oeb.base import OPF, OPF2_NS
         package = etree.Element(OPF('package'), attrib={'version': '2.0'}, nsmap={None: OPF2_NS})
         oeb.metadata.to_opf2(package)
         self.mi = ReadOPF(BytesIO(etree.tostring(package, encoding='utf-8')), populate_spine=False, try_to_guess_cover=False).to_book_metadata()
diff --git a/src/calibre/ebooks/conversion/plugins/epub_input.py b/src/calibre/ebooks/conversion/plugins/epub_input.py
index cace939d0e..f919e64e34 100644
--- a/src/calibre/ebooks/conversion/plugins/epub_input.py
+++ b/src/calibre/ebooks/conversion/plugins/epub_input.py
@@ -2,7 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, re, posixpath
+import os
+import posixpath
+import re
 from itertools import cycle
 
 from calibre.customize.conversion import InputFormatPlugin, OptionRecommendation
@@ -38,8 +40,10 @@ class EPUBInput(InputFormatPlugin):
     recommendations = {('page_breaks_before', '/', OptionRecommendation.MED)}
 
     def process_encryption(self, encfile, opf, log):
+        import hashlib
+        import uuid
+
         from lxml import etree
-        import uuid, hashlib
         idpf_key = opf.raw_unique_identifier
         if idpf_key:
             idpf_key = re.sub('[\u0020\u0009\u000d\u000a]', '', idpf_key)
@@ -148,8 +152,8 @@ class EPUBInput(InputFormatPlugin):
         means, at most one entry with type="cover" that points to a raster
         cover and at most one entry with type="titlepage" that points to an
         HTML titlepage. '''
-        from calibre.utils.localization import __
         from calibre.ebooks.oeb.base import OPF
+        from calibre.utils.localization import __
         removed = None
         from lxml import etree
         guide_cover, guide_elem = None, None
@@ -253,10 +257,10 @@ class EPUBInput(InputFormatPlugin):
             traceback.print_exc()
 
     def convert(self, stream, options, file_ext, log, accelerators):
-        from calibre.utils.zipfile import ZipFile
         from calibre import walk
         from calibre.ebooks import DRMError
         from calibre.ebooks.metadata.opf2 import OPF
+        from calibre.utils.zipfile import ZipFile
         try:
             zf = ZipFile(stream)
             zf.extractall(os.getcwd())
@@ -350,13 +354,15 @@ class EPUBInput(InputFormatPlugin):
         return os.path.abspath('content.opf')
 
     def convert_epub3_nav(self, nav_path, opf, log, opts):
+        from tempfile import NamedTemporaryFile
+
         from lxml import etree
+
         from calibre.ebooks.chardet import xml_to_unicode
+        from calibre.ebooks.oeb.base import EPUB_NS, NCX, NCX_MIME, XHTML, serialize, urlnormalize, urlunquote
         from calibre.ebooks.oeb.polish.parsing import parse
-        from calibre.ebooks.oeb.base import EPUB_NS, XHTML, NCX_MIME, NCX, urlnormalize, urlunquote, serialize
         from calibre.ebooks.oeb.polish.toc import first_child
         from calibre.utils.xml_parse import safe_xml_fromstring
-        from tempfile import NamedTemporaryFile
         with open(nav_path, 'rb') as f:
             raw = f.read()
         raw = xml_to_unicode(raw, strip_encoding_pats=True, assume_utf8=True)[0]
diff --git a/src/calibre/ebooks/conversion/plugins/epub_output.py b/src/calibre/ebooks/conversion/plugins/epub_output.py
index a6ed8e0b51..5eaa9f26dc 100644
--- a/src/calibre/ebooks/conversion/plugins/epub_output.py
+++ b/src/calibre/ebooks/conversion/plugins/epub_output.py
@@ -5,12 +5,13 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, shutil, re
+import os
+import re
+import shutil
 
-from calibre.customize.conversion import (OutputFormatPlugin,
-        OptionRecommendation)
-from calibre.ptempfile import TemporaryDirectory
 from calibre import CurrentDir
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
+from calibre.ptempfile import TemporaryDirectory
 from polyglot.builtins import as_bytes
 
 block_level_tags = (
@@ -157,7 +158,7 @@ class EPUBOutput(OutputFormatPlugin):
 
     def upshift_markup(self):  # {{{
         'Upgrade markup to comply with XHTML 1.1 where possible'
-        from calibre.ebooks.oeb.base import XPath, XML
+        from calibre.ebooks.oeb.base import XML, XPath
         for x in self.oeb.spine:
             root = x.data
             if (not root.get(XML('lang'))) and (root.get('lang')):
@@ -394,7 +395,7 @@ class EPUBOutput(OutputFormatPlugin):
         Perform various markup transforms to get the output to render correctly
         in the quirky ADE.
         '''
-        from calibre.ebooks.oeb.base import XPath, XHTML, barename, urlunquote
+        from calibre.ebooks.oeb.base import XHTML, XPath, barename, urlunquote
 
         stylesheet = self.oeb.manifest.main_stylesheet
         # ADE cries big wet tears when it encounters an invalid fragment
@@ -534,7 +535,7 @@ class EPUBOutput(OutputFormatPlugin):
         '''
         Perform toc link transforms to alleviate slow loading.
         '''
-        from calibre.ebooks.oeb.base import urldefrag, XPath
+        from calibre.ebooks.oeb.base import XPath, urldefrag
         from calibre.ebooks.oeb.polish.toc import item_at_top
 
         def frag_is_at_top(root, frag):
diff --git a/src/calibre/ebooks/conversion/plugins/fb2_input.py b/src/calibre/ebooks/conversion/plugins/fb2_input.py
index 017137b65c..e192c58071 100644
--- a/src/calibre/ebooks/conversion/plugins/fb2_input.py
+++ b/src/calibre/ebooks/conversion/plugins/fb2_input.py
@@ -71,8 +71,9 @@ class FB2Input(InputFormatPlugin):
             css += etree.tostring(s, encoding='unicode', method='text',
                     with_tail=False) + '\n\n'
         if css:
-            import css_parser
             import logging
+
+            import css_parser
             parser = css_parser.CSSParser(fetcher=None,
                     log=logging.getLogger('calibre.css'))
 
diff --git a/src/calibre/ebooks/conversion/plugins/fb2_output.py b/src/calibre/ebooks/conversion/plugins/fb2_output.py
index f4e052ba67..14ae59f1f3 100644
--- a/src/calibre/ebooks/conversion/plugins/fb2_output.py
+++ b/src/calibre/ebooks/conversion/plugins/fb2_output.py
@@ -4,7 +4,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.customize.conversion import OutputFormatPlugin, OptionRecommendation
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 
 
 class FB2Output(OutputFormatPlugin):
@@ -168,9 +168,9 @@ class FB2Output(OutputFormatPlugin):
     }
 
     def convert(self, oeb_book, output_path, input_plugin, opts, log):
+        from calibre.ebooks.fb2.fb2ml import FB2MLizer
         from calibre.ebooks.oeb.transforms.jacket import linearize_jacket
         from calibre.ebooks.oeb.transforms.rasterize import SVGRasterizer, Unavailable
-        from calibre.ebooks.fb2.fb2ml import FB2MLizer
 
         try:
             rasterizer = SVGRasterizer()
diff --git a/src/calibre/ebooks/conversion/plugins/html_input.py b/src/calibre/ebooks/conversion/plugins/html_input.py
index 3ab35fea0d..7700c65cde 100644
--- a/src/calibre/ebooks/conversion/plugins/html_input.py
+++ b/src/calibre/ebooks/conversion/plugins/html_input.py
@@ -14,9 +14,7 @@ from urllib.parse import quote
 
 from calibre.constants import filesystem_encoding, isbsd, islinux
 from calibre.customize.conversion import InputFormatPlugin, OptionRecommendation
-from calibre.utils.filenames import (
-    ascii_filename, case_ignoring_open_file, get_long_path_name,
-)
+from calibre.utils.filenames import ascii_filename, case_ignoring_open_file, get_long_path_name
 from calibre.utils.imghdr import what
 from calibre.utils.localization import __, get_lang
 from polyglot.builtins import as_unicode
@@ -124,18 +122,16 @@ class HTMLInput(InputFormatPlugin):
         return self._is_case_sensitive
 
     def create_oebbook(self, htmlpath, basedir, opts, log, mi):
-        import css_parser
         import logging
         import uuid
 
+        import css_parser
+
         from calibre import guess_type
         from calibre.ebooks.conversion.plumber import create_oebbook
         from calibre.ebooks.html.input import get_filelist
         from calibre.ebooks.metadata import string_to_authors
-        from calibre.ebooks.oeb.base import (
-            BINARY_MIME, OEB_STYLES, DirContainer, rewrite_links, urldefrag,
-            urlnormalize, urlquote, xpath,
-        )
+        from calibre.ebooks.oeb.base import BINARY_MIME, OEB_STYLES, DirContainer, rewrite_links, urldefrag, urlnormalize, urlquote, xpath
         from calibre.ebooks.oeb.transforms.metadata import meta_info_to_oeb_metadata
         from calibre.utils.localization import canonicalize_lang
         self.opts = opts
diff --git a/src/calibre/ebooks/conversion/plugins/html_output.py b/src/calibre/ebooks/conversion/plugins/html_output.py
index d8e2f1880e..9a0a61ee85 100644
--- a/src/calibre/ebooks/conversion/plugins/html_output.py
+++ b/src/calibre/ebooks/conversion/plugins/html_output.py
@@ -5,7 +5,8 @@ __docformat__ = 'restructuredtext en'
 import os
 import re
 import shutil
-from os.path import abspath, basename, dirname, exists, relpath as _relpath
+from os.path import abspath, basename, dirname, exists
+from os.path import relpath as _relpath
 
 from calibre import CurrentDir
 from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
@@ -85,11 +86,11 @@ class HTMLOutput(OutputFormatPlugin):
 
     def convert(self, oeb_book, output_path, input_plugin, opts, log):
         from lxml import etree
+        from templite import Templite
 
         from calibre.ebooks.html.meta import EasyMeta
         from calibre.utils import zipfile
         from polyglot.urllib import unquote
-        from templite import Templite
 
         # read template files
         if opts.template_html_index is not None:
diff --git a/src/calibre/ebooks/conversion/plugins/htmlz_output.py b/src/calibre/ebooks/conversion/plugins/htmlz_output.py
index bb11d1ec6f..3c87c57492 100644
--- a/src/calibre/ebooks/conversion/plugins/htmlz_output.py
+++ b/src/calibre/ebooks/conversion/plugins/htmlz_output.py
@@ -5,8 +5,7 @@ __docformat__ = 'restructuredtext en'
 import io
 import os
 
-from calibre.customize.conversion import OutputFormatPlugin, \
-    OptionRecommendation
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 from calibre.ptempfile import TemporaryDirectory
 
 
@@ -54,10 +53,11 @@ class HTMLZOutput(OutputFormatPlugin):
 
     def convert(self, oeb_book, output_path, input_plugin, opts, log):
         from lxml import etree
-        from calibre.ebooks.oeb.base import OEB_IMAGES, SVG_MIME
+
         from calibre.ebooks.metadata.opf2 import OPF, metadata_to_opf
-        from calibre.utils.zipfile import ZipFile
+        from calibre.ebooks.oeb.base import OEB_IMAGES, SVG_MIME
         from calibre.utils.filenames import ascii_filename
+        from calibre.utils.zipfile import ZipFile
 
         # HTML
         if opts.htmlz_css_type == 'inline':
diff --git a/src/calibre/ebooks/conversion/plugins/lit_input.py b/src/calibre/ebooks/conversion/plugins/lit_input.py
index 8c5fe7d58f..d18cded888 100644
--- a/src/calibre/ebooks/conversion/plugins/lit_input.py
+++ b/src/calibre/ebooks/conversion/plugins/lit_input.py
@@ -18,13 +18,13 @@ class LITInput(InputFormatPlugin):
 
     def convert(self, stream, options, file_ext, log,
                 accelerators):
-        from calibre.ebooks.lit.reader import LitReader
         from calibre.ebooks.conversion.plumber import create_oebbook
+        from calibre.ebooks.lit.reader import LitReader
         self.log = log
         return create_oebbook(log, stream, options, reader=LitReader)
 
     def postprocess_book(self, oeb, opts, log):
-        from calibre.ebooks.oeb.base import XHTML_NS, XPath, XHTML
+        from calibre.ebooks.oeb.base import XHTML, XHTML_NS, XPath
         for item in oeb.spine:
             root = item.data
             if not hasattr(root, 'xpath'):
@@ -39,11 +39,11 @@ class LITInput(InputFormatPlugin):
                 body = body[0]
                 if len(body) == 1 and body[0].tag == XHTML('pre'):
                     pre = body[0]
-                    from calibre.ebooks.txt.processor import convert_basic, \
-                        separate_paragraphs_single_line
-                    from calibre.ebooks.chardet import xml_to_unicode
-                    from calibre.utils.xml_parse import safe_xml_fromstring
                     import copy
+
+                    from calibre.ebooks.chardet import xml_to_unicode
+                    from calibre.ebooks.txt.processor import convert_basic, separate_paragraphs_single_line
+                    from calibre.utils.xml_parse import safe_xml_fromstring
                     self.log('LIT file with all text in single <pre> tag detected')
                     html = separate_paragraphs_single_line(pre.text)
                     html = convert_basic(html).replace('<html>',
diff --git a/src/calibre/ebooks/conversion/plugins/lit_output.py b/src/calibre/ebooks/conversion/plugins/lit_output.py
index cfb72a6037..06230aee07 100644
--- a/src/calibre/ebooks/conversion/plugins/lit_output.py
+++ b/src/calibre/ebooks/conversion/plugins/lit_output.py
@@ -18,10 +18,10 @@ class LITOutput(OutputFormatPlugin):
 
     def convert(self, oeb, output_path, input_plugin, opts, log):
         self.log, self.opts, self.oeb = log, opts, oeb
+        from calibre.ebooks.lit.writer import LitWriter
+        from calibre.ebooks.oeb.transforms.htmltoc import HTMLTOCAdder
         from calibre.ebooks.oeb.transforms.manglecase import CaseMangler
         from calibre.ebooks.oeb.transforms.rasterize import SVGRasterizer
-        from calibre.ebooks.oeb.transforms.htmltoc import HTMLTOCAdder
-        from calibre.ebooks.lit.writer import LitWriter
         from calibre.ebooks.oeb.transforms.split import Split
         split = Split(split_on_page_breaks=True, max_flow_size=0,
                 remove_css_pagebreaks=False)
diff --git a/src/calibre/ebooks/conversion/plugins/lrf_input.py b/src/calibre/ebooks/conversion/plugins/lrf_input.py
index 650a105171..b357fa4f7f 100644
--- a/src/calibre/ebooks/conversion/plugins/lrf_input.py
+++ b/src/calibre/ebooks/conversion/plugins/lrf_input.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, sys
+import os
+import sys
+
 from calibre.customize.conversion import InputFormatPlugin
 from calibre.utils.resources import get_path as P
 
@@ -20,13 +22,13 @@ class LRFInput(InputFormatPlugin):
 
     def convert(self, stream, options, file_ext, log,
                 accelerators):
-        from calibre.ebooks.lrf.input import (MediaType, Styles, TextBlock,
-                Canvas, ImageBlock, RuledLine)
+        from calibre.ebooks.lrf.input import Canvas, ImageBlock, MediaType, RuledLine, Styles, TextBlock
         self.log = log
         self.log('Generating XML')
+        from lxml import etree
+
         from calibre.ebooks.lrf.lrfparser import LRFDocument
         from calibre.utils.xml_parse import safe_xml_fromstring
-        from lxml import etree
         d = LRFDocument(stream)
         d.parse()
         xml = d.to_xml(write_files=True)
diff --git a/src/calibre/ebooks/conversion/plugins/lrf_output.py b/src/calibre/ebooks/conversion/plugins/lrf_output.py
index bfbd07aee4..b3d11d52a3 100644
--- a/src/calibre/ebooks/conversion/plugins/lrf_output.py
+++ b/src/calibre/ebooks/conversion/plugins/lrf_output.py
@@ -5,10 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os
+import os
+import sys
 
-from calibre.customize.conversion import OutputFormatPlugin
-from calibre.customize.conversion import OptionRecommendation
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 
 
 class LRFOptions:
@@ -138,9 +138,10 @@ class LRFOutput(OutputFormatPlugin):
         ('change_justification', 'original', OptionRecommendation.HIGH)}
 
     def convert_images(self, pages, opts, wide):
-        from calibre.ebooks.lrf.pylrs.pylrs import Book, BookSetting, ImageStream, ImageBlock
         from uuid import uuid4
+
         from calibre.constants import __appname__, __version__
+        from calibre.ebooks.lrf.pylrs.pylrs import Book, BookSetting, ImageBlock, ImageStream
 
         width, height = (784, 1012) if wide else (584, 754)
 
diff --git a/src/calibre/ebooks/conversion/plugins/mobi_input.py b/src/calibre/ebooks/conversion/plugins/mobi_input.py
index 5af56b6591..d0a1fd74ed 100644
--- a/src/calibre/ebooks/conversion/plugins/mobi_input.py
+++ b/src/calibre/ebooks/conversion/plugins/mobi_input.py
@@ -20,8 +20,9 @@ class MOBIInput(InputFormatPlugin):
         self.is_kf8 = False
         self.mobi_is_joint = False
 
-        from calibre.ebooks.mobi.reader.mobi6 import MobiReader
         from lxml import html
+
+        from calibre.ebooks.mobi.reader.mobi6 import MobiReader
         parse_cache = {}
         try:
             mr = MobiReader(stream, log, options.input_encoding,
diff --git a/src/calibre/ebooks/conversion/plugins/mobi_output.py b/src/calibre/ebooks/conversion/plugins/mobi_output.py
index c31350b052..0a562cc7cb 100644
--- a/src/calibre/ebooks/conversion/plugins/mobi_output.py
+++ b/src/calibre/ebooks/conversion/plugins/mobi_output.py
@@ -5,8 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.customize.conversion import (OutputFormatPlugin,
-        OptionRecommendation)
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 
 
 def remove_html_cover(oeb, log):
@@ -217,11 +216,11 @@ class MOBIOutput(OutputFormatPlugin):
                 for_joint=for_joint)
 
     def write_mobi(self, input_plugin, output_path, kf8, resources):
+        from calibre.customize.ui import plugin_for_input_format
         from calibre.ebooks.mobi.mobiml import MobiMLizer
+        from calibre.ebooks.oeb.transforms.htmltoc import HTMLTOCAdder
         from calibre.ebooks.oeb.transforms.manglecase import CaseMangler
         from calibre.ebooks.oeb.transforms.rasterize import SVGRasterizer, Unavailable
-        from calibre.ebooks.oeb.transforms.htmltoc import HTMLTOCAdder
-        from calibre.customize.ui import plugin_for_input_format
 
         opts, oeb = self.opts, self.oeb
         if not opts.no_inline_toc:
@@ -308,8 +307,8 @@ class AZW3Output(OutputFormatPlugin):
 
     def convert(self, oeb, output_path, input_plugin, opts, log):
         from calibre.ebooks.mobi.writer2.resources import Resources
-        from calibre.ebooks.mobi.writer8.main import create_kf8_book
         from calibre.ebooks.mobi.writer8.cleanup import remove_duplicate_anchors
+        from calibre.ebooks.mobi.writer8.main import create_kf8_book
 
         self.oeb, self.opts, self.log = oeb, opts, log
         opts.mobi_periodical = self.is_periodical
diff --git a/src/calibre/ebooks/conversion/plugins/oeb_output.py b/src/calibre/ebooks/conversion/plugins/oeb_output.py
index 2e74faca36..e037b91292 100644
--- a/src/calibre/ebooks/conversion/plugins/oeb_output.py
+++ b/src/calibre/ebooks/conversion/plugins/oeb_output.py
@@ -2,12 +2,11 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, re
+import os
+import re
 
-
-from calibre.customize.conversion import (OutputFormatPlugin,
-        OptionRecommendation)
 from calibre import CurrentDir
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 
 
 class OEBOutput(OutputFormatPlugin):
@@ -20,13 +19,14 @@ class OEBOutput(OutputFormatPlugin):
     recommendations = {('pretty_print', True, OptionRecommendation.HIGH)}
 
     def convert(self, oeb_book, output_path, input_plugin, opts, log):
-        from polyglot.urllib import unquote
         from lxml import etree
 
+        from polyglot.urllib import unquote
+
         self.log, self.opts = log, opts
         if not os.path.exists(output_path):
             os.makedirs(output_path)
-        from calibre.ebooks.oeb.base import OPF_MIME, NCX_MIME, PAGE_MAP_MIME, OEB_STYLES
+        from calibre.ebooks.oeb.base import NCX_MIME, OEB_STYLES, OPF_MIME, PAGE_MAP_MIME
         from calibre.ebooks.oeb.normalize_css import condense_sheet
         with CurrentDir(output_path):
             results = oeb_book.to_opf2(page_map=True)
diff --git a/src/calibre/ebooks/conversion/plugins/pdb_input.py b/src/calibre/ebooks/conversion/plugins/pdb_input.py
index b661826058..1e6442dfcf 100644
--- a/src/calibre/ebooks/conversion/plugins/pdb_input.py
+++ b/src/calibre/ebooks/conversion/plugins/pdb_input.py
@@ -17,8 +17,8 @@ class PDBInput(InputFormatPlugin):
 
     def convert(self, stream, options, file_ext, log,
                 accelerators):
+        from calibre.ebooks.pdb import IDENTITY_TO_NAME, PDBError, get_reader
         from calibre.ebooks.pdb.header import PdbHeaderReader
-        from calibre.ebooks.pdb import PDBError, IDENTITY_TO_NAME, get_reader
 
         header = PdbHeaderReader(stream)
         Reader = get_reader(header.ident)
diff --git a/src/calibre/ebooks/conversion/plugins/pdb_output.py b/src/calibre/ebooks/conversion/plugins/pdb_output.py
index 724092eb18..43354afa4d 100644
--- a/src/calibre/ebooks/conversion/plugins/pdb_output.py
+++ b/src/calibre/ebooks/conversion/plugins/pdb_output.py
@@ -4,9 +4,8 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.customize.conversion import OutputFormatPlugin, \
-    OptionRecommendation
-from calibre.ebooks.pdb import PDBError, get_writer, ALL_FORMAT_WRITERS
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
+from calibre.ebooks.pdb import ALL_FORMAT_WRITERS, PDBError, get_writer
 
 
 class PDBOutput(OutputFormatPlugin):
diff --git a/src/calibre/ebooks/conversion/plugins/pdf_input.py b/src/calibre/ebooks/conversion/plugins/pdf_input.py
index bd934869e8..42840b10db 100644
--- a/src/calibre/ebooks/conversion/plugins/pdf_input.py
+++ b/src/calibre/ebooks/conversion/plugins/pdf_input.py
@@ -29,8 +29,8 @@ class PDFInput(InputFormatPlugin):
 
     def convert_new(self, stream, accelerators):
         from calibre.ebooks.pdf.pdftohtml import pdftohtml
-        from calibre.utils.cleantext import clean_ascii_chars
         from calibre.ebooks.pdf.reflow import PDFDocument
+        from calibre.utils.cleantext import clean_ascii_chars
 
         pdftohtml(os.getcwd(), stream.name, self.opts.no_images, as_xml=True)
         with open('index.xml', 'rb') as f:
diff --git a/src/calibre/ebooks/conversion/plugins/pdf_output.py b/src/calibre/ebooks/conversion/plugins/pdf_output.py
index 52389d7ed3..54458f299b 100644
--- a/src/calibre/ebooks/conversion/plugins/pdf_output.py
+++ b/src/calibre/ebooks/conversion/plugins/pdf_output.py
@@ -6,10 +6,10 @@ __docformat__ = 'restructuredtext en'
 Convert OEB ebook format to PDF.
 '''
 
-import glob, os
+import glob
+import os
 
-from calibre.customize.conversion import (OutputFormatPlugin,
-    OptionRecommendation)
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 from calibre.ptempfile import TemporaryDirectory
 from polyglot.builtins import iteritems
 
@@ -169,9 +169,11 @@ class PDFOutput(OutputFormatPlugin):
         self.oeb = oeb_book
         self.input_plugin, self.opts, self.log = input_plugin, opts, log
         self.output_path = output_path
-        from calibre.ebooks.oeb.base import OPF, OPF2_NS
-        from lxml import etree
         from io import BytesIO
+
+        from lxml import etree
+
+        from calibre.ebooks.oeb.base import OPF, OPF2_NS
         package = etree.Element(OPF('package'),
             attrib={'version': '2.0', 'unique-identifier': 'dummy'},
             nsmap={None: OPF2_NS})
@@ -233,6 +235,7 @@ class PDFOutput(OutputFormatPlugin):
 
     def convert_text(self, oeb_book):
         import json
+
         from calibre.ebooks.pdf.html_writer import convert
         if not self.opts.pdf_no_cover:
             self.get_cover_data()
diff --git a/src/calibre/ebooks/conversion/plugins/pml_input.py b/src/calibre/ebooks/conversion/plugins/pml_input.py
index 49f8d2c98c..c4d241f965 100644
--- a/src/calibre/ebooks/conversion/plugins/pml_input.py
+++ b/src/calibre/ebooks/conversion/plugins/pml_input.py
@@ -85,8 +85,8 @@ class PMLInput(InputFormatPlugin):
 
     def convert(self, stream, options, file_ext, log,
                 accelerators):
-        from calibre.ebooks.metadata.toc import TOC
         from calibre.ebooks.metadata.opf2 import OPFCreator
+        from calibre.ebooks.metadata.toc import TOC
         from calibre.utils.zipfile import ZipFile
 
         self.options = options
diff --git a/src/calibre/ebooks/conversion/plugins/pml_output.py b/src/calibre/ebooks/conversion/plugins/pml_output.py
index b1a6a09a40..6ee8a133a2 100644
--- a/src/calibre/ebooks/conversion/plugins/pml_output.py
+++ b/src/calibre/ebooks/conversion/plugins/pml_output.py
@@ -2,10 +2,10 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-import os, io
+import io
+import os
 
-from calibre.customize.conversion import (OutputFormatPlugin,
-        OptionRecommendation)
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 from calibre.ptempfile import TemporaryDirectory
 
 
diff --git a/src/calibre/ebooks/conversion/plugins/rb_output.py b/src/calibre/ebooks/conversion/plugins/rb_output.py
index 6a40d4dfa7..c793ba07e1 100644
--- a/src/calibre/ebooks/conversion/plugins/rb_output.py
+++ b/src/calibre/ebooks/conversion/plugins/rb_output.py
@@ -4,7 +4,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.customize.conversion import OutputFormatPlugin, OptionRecommendation
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 
 
 class RBOutput(OutputFormatPlugin):
diff --git a/src/calibre/ebooks/conversion/plugins/recipe_input.py b/src/calibre/ebooks/conversion/plugins/recipe_input.py
index 9466250e20..9adbe045ab 100644
--- a/src/calibre/ebooks/conversion/plugins/recipe_input.py
+++ b/src/calibre/ebooks/conversion/plugins/recipe_input.py
@@ -7,9 +7,9 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.customize.conversion import InputFormatPlugin, OptionRecommendation
-from calibre.constants import numeric_version
 from calibre import walk
+from calibre.constants import numeric_version
+from calibre.customize.conversion import InputFormatPlugin, OptionRecommendation
 
 
 class RecipeDisabled(Exception):
@@ -71,7 +71,7 @@ class RecipeInput(InputFormatPlugin):
             self.recipe_object = recipe(opts, log, self.report_progress)
         else:
             if os.environ.get('CALIBRE_RECIPE_URN'):
-                from calibre.web.feeds.recipes.collection import get_custom_recipe, get_builtin_recipe_by_id
+                from calibre.web.feeds.recipes.collection import get_builtin_recipe_by_id, get_custom_recipe
                 urn = os.environ['CALIBRE_RECIPE_URN']
                 log('Downloading recipe urn: ' + urn)
                 rtype, recipe_id = urn.partition(':')[::2]
@@ -92,8 +92,7 @@ class RecipeInput(InputFormatPlugin):
                 recipe = compile_recipe(self.recipe_source)
                 log('Using custom recipe')
             else:
-                from calibre.web.feeds.recipes.collection import (
-                        get_builtin_recipe_by_title, get_builtin_recipe_titles)
+                from calibre.web.feeds.recipes.collection import get_builtin_recipe_by_title, get_builtin_recipe_titles
                 title = getattr(opts, 'original_recipe_input_arg', recipe_or_file)
                 title = os.path.basename(title).rpartition('.')[0]
                 titles = frozenset(get_builtin_recipe_titles())
diff --git a/src/calibre/ebooks/conversion/plugins/rtf_input.py b/src/calibre/ebooks/conversion/plugins/rtf_input.py
index 4651bfe89a..5f5d8f206d 100644
--- a/src/calibre/ebooks/conversion/plugins/rtf_input.py
+++ b/src/calibre/ebooks/conversion/plugins/rtf_input.py
@@ -254,8 +254,8 @@ class RTFInput(InputFormatPlugin):
 
         from calibre.ebooks.metadata.meta import get_metadata
         from calibre.ebooks.metadata.opf2 import OPFCreator
-        from calibre.ebooks.rtf2xml.ParseRtf import RtfInvalidCodeException
         from calibre.ebooks.rtf.input import InlineClass
+        from calibre.ebooks.rtf2xml.ParseRtf import RtfInvalidCodeException
         from calibre.utils.xml_parse import safe_xml_fromstring
         self.opts = options
         self.log = log
diff --git a/src/calibre/ebooks/conversion/plugins/snb_output.py b/src/calibre/ebooks/conversion/plugins/snb_output.py
index 363a6b93fd..3a74b634f9 100644
--- a/src/calibre/ebooks/conversion/plugins/snb_output.py
+++ b/src/calibre/ebooks/conversion/plugins/snb_output.py
@@ -4,9 +4,9 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.customize.conversion import OutputFormatPlugin, OptionRecommendation
-from calibre.ptempfile import TemporaryDirectory
 from calibre.constants import __appname__, __version__
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
+from calibre.ptempfile import TemporaryDirectory
 
 
 class SNBOutput(OutputFormatPlugin):
@@ -47,8 +47,9 @@ class SNBOutput(OutputFormatPlugin):
 
     def convert(self, oeb_book, output_path, input_plugin, opts, log):
         from lxml import etree
+
         from calibre.ebooks.snb.snbfile import SNBFile
-        from calibre.ebooks.snb.snbml import SNBMLizer, ProcessFileName
+        from calibre.ebooks.snb.snbml import ProcessFileName, SNBMLizer
 
         self.opts = opts
         from calibre.ebooks.oeb.transforms.rasterize import SVGRasterizer, Unavailable
@@ -221,7 +222,7 @@ class SNBOutput(OutputFormatPlugin):
             snbFile.Output(output_path)
 
     def HandleImage(self, imageData, imagePath):
-        from calibre.utils.img import image_from_data, resize_image, image_to_data
+        from calibre.utils.img import image_from_data, image_to_data, resize_image
         img = image_from_data(imageData)
         x, y = img.width(), img.height()
         if self.opts:
@@ -246,10 +247,10 @@ class SNBOutput(OutputFormatPlugin):
 
 
 if __name__ == '__main__':
-    from calibre.ebooks.oeb.reader import OEBReader
-    from calibre.ebooks.oeb.base import OEBBook
-    from calibre.ebooks.conversion.preprocess import HTMLPreProcessor
     from calibre.customize.profiles import HanlinV3Output
+    from calibre.ebooks.conversion.preprocess import HTMLPreProcessor
+    from calibre.ebooks.oeb.base import OEBBook
+    from calibre.ebooks.oeb.reader import OEBReader
 
     class OptionValues:
         pass
diff --git a/src/calibre/ebooks/conversion/plugins/tcr_output.py b/src/calibre/ebooks/conversion/plugins/tcr_output.py
index 208d8d4fdb..b4e2cdce6e 100644
--- a/src/calibre/ebooks/conversion/plugins/tcr_output.py
+++ b/src/calibre/ebooks/conversion/plugins/tcr_output.py
@@ -4,8 +4,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.customize.conversion import OutputFormatPlugin, \
-    OptionRecommendation
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 
 
 class TCROutput(OutputFormatPlugin):
@@ -22,8 +21,8 @@ class TCROutput(OutputFormatPlugin):
             'The default is utf-8.'))}
 
     def convert(self, oeb_book, output_path, input_plugin, opts, log):
-        from calibre.ebooks.txt.txtml import TXTMLizer
         from calibre.ebooks.compression.tcr import compress
+        from calibre.ebooks.txt.txtml import TXTMLizer
 
         close = False
         if not hasattr(output_path, 'write'):
diff --git a/src/calibre/ebooks/conversion/plugins/txt_input.py b/src/calibre/ebooks/conversion/plugins/txt_input.py
index e4d05d1592..692b8c7e67 100644
--- a/src/calibre/ebooks/conversion/plugins/txt_input.py
+++ b/src/calibre/ebooks/conversion/plugins/txt_input.py
@@ -129,10 +129,17 @@ class TXTInput(InputFormatPlugin):
         from calibre.ebooks.chardet import detect
         from calibre.ebooks.conversion.preprocess import Dehyphenator, DocAnalysis
         from calibre.ebooks.txt.processor import (
-            block_to_single_line, convert_basic, convert_markdown_with_metadata,
-            convert_textile, detect_formatting_type, detect_paragraph_type,
-            normalize_line_endings, preserve_spaces, remove_indents,
-            separate_hard_scene_breaks, separate_paragraphs_print_formatted,
+            block_to_single_line,
+            convert_basic,
+            convert_markdown_with_metadata,
+            convert_textile,
+            detect_formatting_type,
+            detect_paragraph_type,
+            normalize_line_endings,
+            preserve_spaces,
+            remove_indents,
+            separate_hard_scene_breaks,
+            separate_paragraphs_print_formatted,
             separate_paragraphs_single_line,
         )
         from calibre.utils.zipfile import ZipFile
diff --git a/src/calibre/ebooks/conversion/plugins/txt_output.py b/src/calibre/ebooks/conversion/plugins/txt_output.py
index 0de608f34a..d90ff6d802 100644
--- a/src/calibre/ebooks/conversion/plugins/txt_output.py
+++ b/src/calibre/ebooks/conversion/plugins/txt_output.py
@@ -5,9 +5,7 @@ __docformat__ = 'restructuredtext en'
 import os
 import shutil
 
-
-from calibre.customize.conversion import OutputFormatPlugin, \
-    OptionRecommendation
+from calibre.customize.conversion import OptionRecommendation, OutputFormatPlugin
 from calibre.ptempfile import TemporaryDirectory, TemporaryFile
 
 NEWLINE_TYPES = ['system', 'unix', 'old_mac', 'windows']
@@ -81,9 +79,9 @@ class TXTOutput(OutputFormatPlugin):
      }
 
     def convert(self, oeb_book, output_path, input_plugin, opts, log):
+        from calibre.ebooks.txt.newlines import TxtNewlines, specified_newlines
         from calibre.ebooks.txt.txtml import TXTMLizer
         from calibre.utils.cleantext import clean_ascii_chars
-        from calibre.ebooks.txt.newlines import specified_newlines, TxtNewlines
 
         if opts.txt_output_formatting.lower() == 'markdown':
             from calibre.ebooks.txt.markdownml import MarkdownMLizer
diff --git a/src/calibre/ebooks/conversion/plumber.py b/src/calibre/ebooks/conversion/plumber.py
index b3a6945bad..adbfbb540a 100644
--- a/src/calibre/ebooks/conversion/plumber.py
+++ b/src/calibre/ebooks/conversion/plumber.py
@@ -2,21 +2,31 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, re, sys, shutil, pprint, json
+import json
+import os
+import pprint
+import re
+import shutil
+import sys
 from functools import partial
 
-from calibre.customize.conversion import OptionRecommendation, DummyReporter
-from calibre.customize.ui import input_profiles, output_profiles, \
-        plugin_for_input_format, plugin_for_output_format, \
-        available_input_formats, available_output_formats, \
-        run_plugins_on_preprocess, run_plugins_on_postprocess
+from calibre import extract, filesystem_encoding, get_types_map, isbytestring, walk
+from calibre.constants import __version__
+from calibre.customize.conversion import DummyReporter, OptionRecommendation
+from calibre.customize.ui import (
+    available_input_formats,
+    available_output_formats,
+    input_profiles,
+    output_profiles,
+    plugin_for_input_format,
+    plugin_for_output_format,
+    run_plugins_on_postprocess,
+    run_plugins_on_preprocess,
+)
 from calibre.ebooks.conversion.preprocess import HTMLPreProcessor
 from calibre.ptempfile import PersistentTemporaryDirectory
 from calibre.utils.date import parse_date
 from calibre.utils.zipfile import ZipFile
-from calibre import (extract, walk, isbytestring, filesystem_encoding,
-        get_types_map)
-from calibre.constants import __version__
 from polyglot.builtins import string_or_bytes
 
 DEBUG_README=b'''
@@ -923,9 +933,11 @@ OptionRecommendation(name='search_replace',
                 setattr(mi, x, val)
 
     def download_cover(self, url):
-        from calibre import browser
-        from PIL import Image
         import io
+
+        from PIL import Image
+
+        from calibre import browser
         from calibre.ptempfile import PersistentTemporaryFile
         self.log('Downloading cover from %r'%url)
         br = browser()
@@ -1055,7 +1067,9 @@ OptionRecommendation(name='search_replace',
         if self.opts.embed_all_fonts or self.opts.embed_font_family:
             # Start the threaded font scanner now, for performance
             from calibre.utils.fonts.scanner import font_scanner  # noqa
-        import css_parser, logging
+        import logging
+
+        import css_parser
         css_parser.log.setLevel(logging.WARN)
         get_types_map()  # Ensure the mimetypes module is initialized
 
@@ -1242,8 +1256,7 @@ OptionRecommendation(name='search_replace',
         self.opts.insert_blank_line = oibl
         self.opts.remove_paragraph_spacing = orps
 
-        from calibre.ebooks.oeb.transforms.page_margin import \
-            RemoveFakeMargins, RemoveAdobeMargins
+        from calibre.ebooks.oeb.transforms.page_margin import RemoveAdobeMargins, RemoveFakeMargins
         RemoveFakeMargins()(self.oeb, self.log, self.opts)
         RemoveAdobeMargins()(self.oeb, self.log, self.opts)
 
diff --git a/src/calibre/ebooks/conversion/preprocess.py b/src/calibre/ebooks/conversion/preprocess.py
index a7782eae65..4f0856f529 100644
--- a/src/calibre/ebooks/conversion/preprocess.py
+++ b/src/calibre/ebooks/conversion/preprocess.py
@@ -5,10 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import functools, re, json
+import functools
+import json
+import re
 from math import ceil
 
-from calibre import entity_to_unicode, as_unicode
+from calibre import as_unicode, entity_to_unicode
 
 XMLDECL_RE    = re.compile(r'^\s*<[?]xml.*?[?]>')
 SVG_NS       = 'http://www.w3.org/2000/svg'
@@ -68,9 +70,9 @@ def wrap_lines(match):
 
 
 def smarten_punctuation(html, log=None):
-    from calibre.utils.smartypants import smartyPants
     from calibre.ebooks.chardet import substitute_entites
     from calibre.ebooks.conversion.utils import HeuristicProcessor
+    from calibre.utils.smartypants import smartyPants
     preprocessor = HeuristicProcessor(log=log)
     from uuid import uuid4
     start = 'calibre-smartypants-'+str(uuid4())
diff --git a/src/calibre/ebooks/conversion/utils.py b/src/calibre/ebooks/conversion/utils.py
index 86dfdd9018..5c074a69f1 100644
--- a/src/calibre/ebooks/conversion/utils.py
+++ b/src/calibre/ebooks/conversion/utils.py
@@ -7,7 +7,8 @@ __docformat__ = 'restructuredtext en'
 
 import re
 from math import ceil
-from calibre.ebooks.conversion.preprocess import DocAnalysis, Dehyphenator
+
+from calibre.ebooks.conversion.preprocess import Dehyphenator, DocAnalysis
 from calibre.utils.logging import default_log
 from calibre.utils.wordcount import get_wordcount_obj
 
diff --git a/src/calibre/ebooks/covers.py b/src/calibre/ebooks/covers.py
index 9f99489373..048d1f0bef 100644
--- a/src/calibre/ebooks/covers.py
+++ b/src/calibre/ebooks/covers.py
@@ -12,10 +12,26 @@ from collections import namedtuple
 from contextlib import contextmanager
 from itertools import chain
 from math import atan2, ceil, cos, sin, sqrt
+
 from qt.core import (
-    QBrush, QColor, QFont, QFontMetrics, QImage, QLinearGradient, QPainter,
-    QPainterPath, QPen, QPointF, QRadialGradient, QRect, QRectF, Qt, QTextCharFormat,
-    QTextLayout, QTextOption, QTransform,
+    QBrush,
+    QColor,
+    QFont,
+    QFontMetrics,
+    QImage,
+    QLinearGradient,
+    QPainter,
+    QPainterPath,
+    QPen,
+    QPointF,
+    QRadialGradient,
+    QRect,
+    QRectF,
+    Qt,
+    QTextCharFormat,
+    QTextLayout,
+    QTextOption,
+    QTransform,
 )
 
 from calibre import fit_image, force_unicode
diff --git a/src/calibre/ebooks/css_transform_rules.py b/src/calibre/ebooks/css_transform_rules.py
index 712e1253ed..39178789a5 100644
--- a/src/calibre/ebooks/css_transform_rules.py
+++ b/src/calibre/ebooks/css_transform_rules.py
@@ -2,11 +2,12 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from functools import partial
+import numbers
+import operator
 from collections import OrderedDict
-import operator, numbers
+from functools import partial
 
-from css_parser.css import Property, CSSRule
+from css_parser.css import CSSRule, Property
 
 from calibre import force_unicode
 from calibre.ebooks import parse_css_length
diff --git a/src/calibre/ebooks/djvu/djvu.py b/src/calibre/ebooks/djvu/djvu.py
index 967338ac1b..df029e5de9 100644
--- a/src/calibre/ebooks/djvu/djvu.py
+++ b/src/calibre/ebooks/djvu/djvu.py
@@ -9,8 +9,8 @@ __copyright__ = '2011, Anthon van der Neut <A.van.der.Neut@ruamel.eu>'
 # DjVu v3
 # November 2005
 
-import sys
 import struct
+import sys
 
 from calibre.ebooks.djvu.djvubzzdec import BZZDecoder
 
diff --git a/src/calibre/ebooks/djvu/djvubzzdec.py b/src/calibre/ebooks/djvu/djvubzzdec.py
index 1e1e9eb3bd..5748af9682 100644
--- a/src/calibre/ebooks/djvu/djvubzzdec.py
+++ b/src/calibre/ebooks/djvu/djvubzzdec.py
@@ -731,6 +731,7 @@ class BZZDecoder():
 # for testing
 def main():
     import sys
+
     from calibre_extensions import bzzdec as d
     with open(sys.argv[1], "rb") as f:
         raw = f.read()
diff --git a/src/calibre/ebooks/docx/block_styles.py b/src/calibre/ebooks/docx/block_styles.py
index 1bd6e856c5..6e5f548cd8 100644
--- a/src/calibre/ebooks/docx/block_styles.py
+++ b/src/calibre/ebooks/docx/block_styles.py
@@ -6,6 +6,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import numbers
 from collections import OrderedDict
+
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/docx/char_styles.py b/src/calibre/ebooks/docx/char_styles.py
index a651b4349c..1cc7f5ba2a 100644
--- a/src/calibre/ebooks/docx/char_styles.py
+++ b/src/calibre/ebooks/docx/char_styles.py
@@ -5,8 +5,8 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import OrderedDict
-from calibre.ebooks.docx.block_styles import (  # noqa
-    inherit, simple_color, LINE_STYLES, simple_float, binary_property, read_shd)
+
+from calibre.ebooks.docx.block_styles import LINE_STYLES, binary_property, inherit, read_shd, simple_color, simple_float  # noqa
 
 # Read from XML {{{
 
diff --git a/src/calibre/ebooks/docx/cleanup.py b/src/calibre/ebooks/docx/cleanup.py
index 8f9d463c90..322e44ba9a 100644
--- a/src/calibre/ebooks/docx/cleanup.py
+++ b/src/calibre/ebooks/docx/cleanup.py
@@ -5,6 +5,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
+
 from polyglot.builtins import itervalues
 
 NBSP = '\xa0'
diff --git a/src/calibre/ebooks/docx/container.py b/src/calibre/ebooks/docx/container.py
index c73ad84a21..bdea8cdb25 100644
--- a/src/calibre/ebooks/docx/container.py
+++ b/src/calibre/ebooks/docx/container.py
@@ -4,20 +4,22 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, sys, shutil
+import os
+import shutil
+import sys
 
 from lxml import etree
 
-from calibre import walk, guess_type
-from calibre.ebooks.metadata import string_to_authors, authors_to_sort_string
-from calibre.ebooks.metadata.book.base import Metadata
+from calibre import guess_type, walk
 from calibre.ebooks.docx import InvalidDOCX
 from calibre.ebooks.docx.names import DOCXNamespace
+from calibre.ebooks.metadata import authors_to_sort_string, string_to_authors
+from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ptempfile import PersistentTemporaryDirectory
 from calibre.utils.localization import canonicalize_lang
 from calibre.utils.logging import default_log
-from calibre.utils.zipfile import ZipFile
 from calibre.utils.xml_parse import safe_xml_fromstring
+from calibre.utils.zipfile import ZipFile
 
 
 def fromstring(raw, parser=None):
diff --git a/src/calibre/ebooks/docx/dump.py b/src/calibre/ebooks/docx/dump.py
index e64c4d2136..2e566571dc 100644
--- a/src/calibre/ebooks/docx/dump.py
+++ b/src/calibre/ebooks/docx/dump.py
@@ -4,13 +4,15 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import sys, os, shutil
+import os
+import shutil
+import sys
 
 from lxml import etree
 
 from calibre import walk
-from calibre.utils.zipfile import ZipFile
 from calibre.utils.xml_parse import safe_xml_fromstring
+from calibre.utils.zipfile import ZipFile
 
 
 def pretty_all_xml_in_dir(path):
diff --git a/src/calibre/ebooks/docx/fields.py b/src/calibre/ebooks/docx/fields.py
index 95012eeb2c..6d931c3013 100644
--- a/src/calibre/ebooks/docx/fields.py
+++ b/src/calibre/ebooks/docx/fields.py
@@ -6,7 +6,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 
-from calibre.ebooks.docx.index import process_index, polish_index_markup
+from calibre.ebooks.docx.index import polish_index_markup, process_index
 from polyglot.builtins import iteritems, native_string_type
 
 
diff --git a/src/calibre/ebooks/docx/fonts.py b/src/calibre/ebooks/docx/fonts.py
index 951349e521..b6733323f9 100644
--- a/src/calibre/ebooks/docx/fonts.py
+++ b/src/calibre/ebooks/docx/fonts.py
@@ -4,13 +4,14 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, re
+import os
+import re
 from collections import namedtuple
 
 from calibre.ebooks.docx.block_styles import binary_property, inherit
 from calibre.utils.filenames import ascii_filename
-from calibre.utils.fonts.scanner import font_scanner, NoFonts
-from calibre.utils.fonts.utils import panose_to_css_generic_family, is_truetype_font
+from calibre.utils.fonts.scanner import NoFonts, font_scanner
+from calibre.utils.fonts.utils import is_truetype_font, panose_to_css_generic_family
 from calibre.utils.icu import ord_string
 from polyglot.builtins import codepoint_to_chr, iteritems
 
diff --git a/src/calibre/ebooks/docx/images.py b/src/calibre/ebooks/docx/images.py
index c8e1694b94..4e3c8de9ea 100644
--- a/src/calibre/ebooks/docx/images.py
+++ b/src/calibre/ebooks/docx/images.py
@@ -6,6 +6,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 import re
+
 from lxml.html.builder import HR, IMG
 
 from calibre import sanitize_file_name
diff --git a/src/calibre/ebooks/docx/numbering.py b/src/calibre/ebooks/docx/numbering.py
index 42a41d9717..a7cf7451bf 100644
--- a/src/calibre/ebooks/docx/numbering.py
+++ b/src/calibre/ebooks/docx/numbering.py
@@ -4,11 +4,12 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import re, string
+import re
+import string
 from collections import Counter, defaultdict
 from functools import partial
 
-from lxml.html.builder import OL, UL, SPAN
+from lxml.html.builder import OL, SPAN, UL
 
 from calibre.ebooks.docx.block_styles import ParagraphStyle
 from calibre.ebooks.docx.char_styles import RunStyle, inherit
diff --git a/src/calibre/ebooks/docx/styles.py b/src/calibre/ebooks/docx/styles.py
index 9df8bebd7d..738d481e92 100644
--- a/src/calibre/ebooks/docx/styles.py
+++ b/src/calibre/ebooks/docx/styles.py
@@ -5,7 +5,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import textwrap
-from collections import OrderedDict, Counter
+from collections import Counter, OrderedDict
 
 from calibre.ebooks.docx.block_styles import ParagraphStyle, inherit, twips
 from calibre.ebooks.docx.char_styles import RunStyle
diff --git a/src/calibre/ebooks/docx/tables.py b/src/calibre/ebooks/docx/tables.py
index d3574cd217..11e657e2a9 100644
--- a/src/calibre/ebooks/docx/tables.py
+++ b/src/calibre/ebooks/docx/tables.py
@@ -4,9 +4,10 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from lxml.html.builder import TABLE, TR, TD
+from lxml.html.builder import TABLE, TD, TR
 
-from calibre.ebooks.docx.block_styles import inherit, read_shd as rs, read_border, binary_property, border_props, ParagraphStyle, border_to_css
+from calibre.ebooks.docx.block_styles import ParagraphStyle, binary_property, border_props, border_to_css, inherit, read_border
+from calibre.ebooks.docx.block_styles import read_shd as rs
 from calibre.ebooks.docx.char_styles import RunStyle
 from polyglot.builtins import iteritems, itervalues
 
diff --git a/src/calibre/ebooks/docx/writer/container.py b/src/calibre/ebooks/docx/writer/container.py
index 2fde66d5bd..0b8bff1917 100644
--- a/src/calibre/ebooks/docx/writer/container.py
+++ b/src/calibre/ebooks/docx/writer/container.py
@@ -4,13 +4,14 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import textwrap, os
+import os
+import textwrap
 
 from lxml import etree
 from lxml.builder import ElementMaker
 
 from calibre import guess_type
-from calibre.constants import numeric_version, __appname__
+from calibre.constants import __appname__, numeric_version
 from calibre.ebooks.docx.names import DOCXNamespace
 from calibre.ebooks.metadata import authors_to_string
 from calibre.ebooks.pdf.render.common import PAPER_SIZES
diff --git a/src/calibre/ebooks/docx/writer/from_html.py b/src/calibre/ebooks/docx/writer/from_html.py
index 92cf5ca72b..b82e6ca7aa 100644
--- a/src/calibre/ebooks/docx/writer/from_html.py
+++ b/src/calibre/ebooks/docx/writer/from_html.py
@@ -7,15 +7,16 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import re
 from collections import Counter
 
-from calibre.ebooks.docx.writer.container import create_skeleton, page_size, page_effective_area
-from calibre.ebooks.docx.writer.styles import StylesManager, FloatSpec
-from calibre.ebooks.docx.writer.links import LinksManager
-from calibre.ebooks.docx.writer.images import ImagesManager
+from calibre.ebooks.docx.writer.container import create_skeleton, page_effective_area, page_size
 from calibre.ebooks.docx.writer.fonts import FontsManager
-from calibre.ebooks.docx.writer.tables import Table
+from calibre.ebooks.docx.writer.images import ImagesManager
+from calibre.ebooks.docx.writer.links import LinksManager
 from calibre.ebooks.docx.writer.lists import ListsManager
-from calibre.ebooks.oeb.stylizer import Stylizer as Sz, Style as St
+from calibre.ebooks.docx.writer.styles import FloatSpec, StylesManager
+from calibre.ebooks.docx.writer.tables import Table
 from calibre.ebooks.oeb.base import XPath, barename
+from calibre.ebooks.oeb.stylizer import Style as St
+from calibre.ebooks.oeb.stylizer import Stylizer as Sz
 from calibre.utils.localization import lang_as_iso639_1
 from polyglot.builtins import string_or_bytes
 
diff --git a/src/calibre/ebooks/docx/writer/images.py b/src/calibre/ebooks/docx/writer/images.py
index 6345733c77..5e4d6d946d 100644
--- a/src/calibre/ebooks/docx/writer/images.py
+++ b/src/calibre/ebooks/docx/writer/images.py
@@ -8,11 +8,12 @@ import os
 import posixpath
 from collections import namedtuple
 from functools import partial
+
 from lxml import etree
 
 from calibre import fit_image
 from calibre.ebooks.docx.images import pt_to_emu
-from calibre.ebooks.docx.names import USE_LOCAL_DPI_URI, SVG_BLIP_URI
+from calibre.ebooks.docx.names import SVG_BLIP_URI, USE_LOCAL_DPI_URI
 from calibre.ebooks.oeb.base import urlquote, urlunquote
 from calibre.utils.filenames import ascii_filename
 from calibre.utils.imghdr import identify
diff --git a/src/calibre/ebooks/docx/writer/styles.py b/src/calibre/ebooks/docx/writer/styles.py
index 56ba08aba7..73f85d49eb 100644
--- a/src/calibre/ebooks/docx/writer/styles.py
+++ b/src/calibre/ebooks/docx/writer/styles.py
@@ -9,12 +9,12 @@ from collections import Counter, defaultdict
 from operator import attrgetter
 
 from lxml import etree
+from tinycss.css21 import CSS21Parser
 
 from calibre.ebooks import parse_css_length
 from calibre.ebooks.docx.writer.utils import convert_color, int_or_zero
 from calibre.utils.localization import lang_as_iso639_1
 from polyglot.builtins import iteritems
-from tinycss.css21 import CSS21Parser
 
 css_parser = CSS21Parser()
 
diff --git a/src/calibre/ebooks/docx/writer/tables.py b/src/calibre/ebooks/docx/writer/tables.py
index 4e95eb6adf..3f65d6a381 100644
--- a/src/calibre/ebooks/docx/writer/tables.py
+++ b/src/calibre/ebooks/docx/writer/tables.py
@@ -6,8 +6,9 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import namedtuple
 
+from calibre.ebooks.docx.writer.styles import border_edges
+from calibre.ebooks.docx.writer.styles import read_css_block_borders as rcbb
 from calibre.ebooks.docx.writer.utils import convert_color
-from calibre.ebooks.docx.writer.styles import read_css_block_borders as rcbb, border_edges
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/epub/__init__.py b/src/calibre/ebooks/epub/__init__.py
index 71c1a5f210..a8cd6cec96 100644
--- a/src/calibre/ebooks/epub/__init__.py
+++ b/src/calibre/ebooks/epub/__init__.py
@@ -5,7 +5,7 @@ __docformat__ = 'restructuredtext en'
 '''
 Conversion to EPUB.
 '''
-from calibre.utils.zipfile import ZipFile, ZIP_STORED
+from calibre.utils.zipfile import ZIP_STORED, ZipFile
 
 
 def rules(stylesheets):
diff --git a/src/calibre/ebooks/epub/cfi/tests.py b/src/calibre/ebooks/epub/cfi/tests.py
index 71547176fa..18a4e5dd16 100644
--- a/src/calibre/ebooks/epub/cfi/tests.py
+++ b/src/calibre/ebooks/epub/cfi/tests.py
@@ -4,9 +4,10 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import unittest, numbers
+import numbers
+import unittest
 
-from calibre.ebooks.epub.cfi.parse import parser, cfi_sort_key, decode_cfi
+from calibre.ebooks.epub.cfi.parse import cfi_sort_key, decode_cfi, parser
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/epub/pages.py b/src/calibre/ebooks/epub/pages.py
index da06eef01e..7f58aa728c 100644
--- a/src/calibre/ebooks/epub/pages.py
+++ b/src/calibre/ebooks/epub/pages.py
@@ -9,10 +9,11 @@ __docformat__ = 'restructuredtext en'
 
 import re
 from itertools import count
-from calibre.ebooks.oeb.base import XHTML_NS
-from calibre.ebooks.oeb.base import OEBBook
+
 from lxml.etree import XPath
 
+from calibre.ebooks.oeb.base import XHTML_NS, OEBBook
+
 NSMAP = {'h': XHTML_NS, 'html': XHTML_NS, 'xhtml': XHTML_NS}
 PAGE_RE = re.compile(r'page', re.IGNORECASE)
 ROMAN_RE = re.compile(r'^[ivxlcdm]+$', re.IGNORECASE)
diff --git a/src/calibre/ebooks/epub/periodical.py b/src/calibre/ebooks/epub/periodical.py
index 8b2a661040..80db09a5e9 100644
--- a/src/calibre/ebooks/epub/periodical.py
+++ b/src/calibre/ebooks/epub/periodical.py
@@ -5,11 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from uuid import uuid4
 import time
+from uuid import uuid4
 
+from calibre import prepare_string_for_xml as xml
+from calibre import strftime
 from calibre.constants import __appname__, __version__
-from calibre import strftime, prepare_string_for_xml as xml
 from calibre.utils.date import parse_date
 
 SONY_METADATA = '''\
diff --git a/src/calibre/ebooks/fb2/__init__.py b/src/calibre/ebooks/fb2/__init__.py
index 4e93dd8225..3ef0e9b45b 100644
--- a/src/calibre/ebooks/fb2/__init__.py
+++ b/src/calibre/ebooks/fb2/__init__.py
@@ -8,6 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 def base64_decode(raw):
     from io import BytesIO
+
     from polyglot.binary import from_base64_bytes
 
     # First try the python implementation as it is faster
diff --git a/src/calibre/ebooks/fb2/fb2ml.py b/src/calibre/ebooks/fb2/fb2ml.py
index 78e369eb86..a24fd2d72c 100644
--- a/src/calibre/ebooks/fb2/fb2ml.py
+++ b/src/calibre/ebooks/fb2/fb2ml.py
@@ -6,19 +6,21 @@ __docformat__ = 'restructuredtext en'
 Transform OEB content into FB2 markup
 '''
 
-import re, textwrap, uuid
+import re
+import textwrap
+import uuid
 from datetime import datetime
 
 from lxml import etree
 
 from calibre import prepare_string_for_xml
 from calibre.constants import __appname__, __version__
+from calibre.ebooks.oeb.base import urlnormalize
+from calibre.utils.img import save_cover_data_to
 from calibre.utils.localization import lang_as_iso639_1
 from calibre.utils.xml_parse import safe_xml_fromstring
-from calibre.utils.img import save_cover_data_to
-from calibre.ebooks.oeb.base import urlnormalize
-from polyglot.builtins import string_or_bytes
 from polyglot.binary import as_base64_unicode
+from polyglot.builtins import string_or_bytes
 from polyglot.urllib import urlparse
 
 
diff --git a/src/calibre/ebooks/html/meta.py b/src/calibre/ebooks/html/meta.py
index cad6cc6c5a..c834364d3a 100644
--- a/src/calibre/ebooks/html/meta.py
+++ b/src/calibre/ebooks/html/meta.py
@@ -9,7 +9,7 @@ class EasyMeta:
         self.meta = meta
 
     def __iter__(self):
-        from calibre.ebooks.oeb.base import namespace, barename, DC11_NS
+        from calibre.ebooks.oeb.base import DC11_NS, barename, namespace
         meta = self.meta
         for item_name in meta.items:
             for item in meta[item_name]:
diff --git a/src/calibre/ebooks/html/to_zip.py b/src/calibre/ebooks/html/to_zip.py
index d70265bb56..8903a995c8 100644
--- a/src/calibre/ebooks/html/to_zip.py
+++ b/src/calibre/ebooks/html/to_zip.py
@@ -5,10 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import textwrap, os, glob
+import glob
+import os
+import textwrap
 
-from calibre.customize import FileTypePlugin
 from calibre.constants import numeric_version
+from calibre.customize import FileTypePlugin
 
 
 class HTML2ZIP(FileTypePlugin):
@@ -40,11 +42,12 @@ every time you add an HTML file to the library.\
 
     def run(self, htmlfile):
         import codecs
+
         from calibre import prints
-        from calibre.ptempfile import TemporaryDirectory
-        from calibre.gui2.convert.gui_conversion import gui_convert
         from calibre.customize.conversion import OptionRecommendation
         from calibre.ebooks.epub import initialize_container
+        from calibre.gui2.convert.gui_conversion import gui_convert
+        from calibre.ptempfile import TemporaryDirectory
 
         with TemporaryDirectory('_plugin_html2zip') as tdir:
             recs =[('debug_pipeline', tdir, OptionRecommendation.HIGH)]
@@ -87,8 +90,8 @@ every time you add an HTML file to the library.\
         automatically applied.
         '''
         import json
-        from qt.core import (QDialog, QDialogButtonBox, QVBoxLayout,
-                QLabel, Qt, QLineEdit, QCheckBox)
+
+        from qt.core import QCheckBox, QDialog, QDialogButtonBox, QLabel, QLineEdit, Qt, QVBoxLayout
 
         config_dialog = QDialog(parent)
         button_box = QDialogButtonBox(QDialogButtonBox.StandardButton.Ok | QDialogButtonBox.StandardButton.Cancel)
@@ -100,8 +103,7 @@ every time you add an HTML file to the library.\
         button_box.accepted.connect(config_dialog.accept)
         button_box.rejected.connect(config_dialog.reject)
         config_dialog.setWindowTitle(_('Customize') + ' ' + self.name)
-        from calibre.customize.ui import (plugin_customization,
-                customize_plugin)
+        from calibre.customize.ui import customize_plugin, plugin_customization
         help_text = self.customization_help(gui=True)
         help_text = QLabel(help_text, config_dialog)
         help_text.setWordWrap(True)
diff --git a/src/calibre/ebooks/html_entities.py b/src/calibre/ebooks/html_entities.py
index ca2dc2fdf7..7d9bf0d6d7 100644
--- a/src/calibre/ebooks/html_entities.py
+++ b/src/calibre/ebooks/html_entities.py
@@ -2135,6 +2135,7 @@ html5_entities = {
 
 if __name__ == '__main__':
     import re
+
     from html5lib.constants import entities
     entities = {k.replace(';', ''): entities[k] for k in entities}
     lines = []
diff --git a/src/calibre/ebooks/html_transform_rules.py b/src/calibre/ebooks/html_transform_rules.py
index bb48b95d62..f5e2634c88 100644
--- a/src/calibre/ebooks/html_transform_rules.py
+++ b/src/calibre/ebooks/html_transform_rules.py
@@ -4,13 +4,14 @@
 
 import re
 from functools import partial
+
+from css_selectors.select import Select, get_parsed_selector
 from html5_parser import parse
 from lxml import etree
 
-from calibre.ebooks.oeb.parse_utils import XHTML
-from calibre.ebooks.oeb.base import OEB_DOCS, XPath
 from calibre.ebooks.metadata.tag_mapper import uniq
-from css_selectors.select import Select, get_parsed_selector
+from calibre.ebooks.oeb.base import OEB_DOCS, XPath
+from calibre.ebooks.oeb.parse_utils import XHTML
 
 
 def non_empty_validator(label, val):
diff --git a/src/calibre/ebooks/htmlz/oeb2html.py b/src/calibre/ebooks/htmlz/oeb2html.py
index 3ea8c2c952..29eb1ff1f8 100644
--- a/src/calibre/ebooks/htmlz/oeb2html.py
+++ b/src/calibre/ebooks/htmlz/oeb2html.py
@@ -8,15 +8,13 @@ Transform OEB content into a single (more or less) HTML file.
 
 import os
 import re
-from css_parser import replaceUrls
 from functools import partial
+
+from css_parser import replaceUrls
 from lxml import html
 
 from calibre import prepare_string_for_xml
-from calibre.ebooks.oeb.base import (
-    OEB_IMAGES, SVG_NS, XHTML, XHTML_NS, XLINK, barename, namespace, rewrite_links,
-    urlnormalize,
-)
+from calibre.ebooks.oeb.base import OEB_IMAGES, SVG_NS, XHTML, XHTML_NS, XLINK, barename, namespace, rewrite_links, urlnormalize
 from calibre.ebooks.oeb.stylizer import Stylizer
 from calibre.utils.logging import default_log
 from polyglot.builtins import as_unicode, string_or_bytes
diff --git a/src/calibre/ebooks/lit/maps/__init__.py b/src/calibre/ebooks/lit/maps/__init__.py
index b30974ba6b..13114268d9 100644
--- a/src/calibre/ebooks/lit/maps/__init__.py
+++ b/src/calibre/ebooks/lit/maps/__init__.py
@@ -5,7 +5,7 @@ __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 Microsoft LIT tag and attribute tables.
 """
 
-from calibre.ebooks.lit.maps.opf import MAP as OPF_MAP
 from calibre.ebooks.lit.maps.html import MAP as HTML_MAP
+from calibre.ebooks.lit.maps.opf import MAP as OPF_MAP
 
 OPF_MAP, HTML_MAP
diff --git a/src/calibre/ebooks/lit/mssha1.py b/src/calibre/ebooks/lit/mssha1.py
index 5ac50ddccf..ccd735cd94 100644
--- a/src/calibre/ebooks/lit/mssha1.py
+++ b/src/calibre/ebooks/lit/mssha1.py
@@ -7,7 +7,9 @@ Adapted from the PyPy pure-Python SHA-1 implementation.
 __license__   = 'GPL v3'
 __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
-import struct, copy
+import copy
+import struct
+
 from polyglot.builtins import long_type
 
 # ======================================================================
diff --git a/src/calibre/ebooks/lit/reader.py b/src/calibre/ebooks/lit/reader.py
index 9a4cc4604c..a0899a7491 100644
--- a/src/calibre/ebooks/lit/reader.py
+++ b/src/calibre/ebooks/lit/reader.py
@@ -6,19 +6,24 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net> ' \
     'and Marshall T. Vandegrift <llasram@gmail.com>'
 
-import io, struct, os, functools, re
+import functools
+import io
+import os
+import re
+import struct
 
 from lxml import etree
 
-from calibre.ebooks.lit import LitError
-from calibre.ebooks.lit.maps import OPF_MAP, HTML_MAP
 import calibre.ebooks.lit.mssha1 as mssha1
+from calibre.ebooks import DRMError
+from calibre.ebooks.lit import LitError
+from calibre.ebooks.lit.maps import HTML_MAP, OPF_MAP
 from calibre.ebooks.oeb.base import urlnormalize, xpath
 from calibre.ebooks.oeb.reader import OEBReader
-from calibre.ebooks import DRMError
-from polyglot.builtins import codepoint_to_chr, string_or_bytes, itervalues
-from polyglot.urllib import unquote as urlunquote, urldefrag
 from calibre_extensions import lzx, msdes
+from polyglot.builtins import codepoint_to_chr, itervalues, string_or_bytes
+from polyglot.urllib import unquote as urlunquote
+from polyglot.urllib import urldefrag
 
 __all__ = ["LitReader"]
 
diff --git a/src/calibre/ebooks/lit/writer.py b/src/calibre/ebooks/lit/writer.py
index 21af07a400..044f88d340 100644
--- a/src/calibre/ebooks/lit/writer.py
+++ b/src/calibre/ebooks/lit/writer.py
@@ -5,31 +5,30 @@ Basic support for writing LIT files.
 __license__   = 'GPL v3'
 __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
-from struct import pack
-from itertools import count, chain
-from operator import attrgetter
+import copy
+import functools
 import io
-import time
+import numbers
 import os
 import re
-import copy
+import time
 import uuid
-import functools
-import numbers
+from itertools import chain, count
+from operator import attrgetter
+from struct import pack
+
 from lxml import etree
-from calibre.ebooks.lit.reader import DirectoryEntry
-import calibre.ebooks.lit.maps as maps
-from calibre.ebooks.oeb.base import OEB_DOCS, XHTML_MIME, OEB_STYLES, \
-    CSS_MIME, OPF_MIME, XML_NS, XML
-from calibre.ebooks.oeb.base import prefixname, \
-    urlnormalize
-from calibre.ebooks.oeb.stylizer import Stylizer
-from calibre.ebooks.lit.lzx import Compressor
+
 import calibre
-from calibre_extensions import msdes
+import calibre.ebooks.lit.maps as maps
 import calibre.ebooks.lit.mssha1 as mssha1
-from polyglot.builtins import codepoint_to_chr, string_or_bytes, native_string_type
-from polyglot.urllib import urldefrag, unquote
+from calibre.ebooks.lit.lzx import Compressor
+from calibre.ebooks.lit.reader import DirectoryEntry
+from calibre.ebooks.oeb.base import CSS_MIME, OEB_DOCS, OEB_STYLES, OPF_MIME, XHTML_MIME, XML, XML_NS, prefixname, urlnormalize
+from calibre.ebooks.oeb.stylizer import Stylizer
+from calibre_extensions import msdes
+from polyglot.builtins import codepoint_to_chr, native_string_type, string_or_bytes
+from polyglot.urllib import unquote, urldefrag
 
 __all__ = ['LitWriter']
 
diff --git a/src/calibre/ebooks/lrf/__init__.py b/src/calibre/ebooks/lrf/__init__.py
index 4f90be7d97..4a324b3f40 100644
--- a/src/calibre/ebooks/lrf/__init__.py
+++ b/src/calibre/ebooks/lrf/__init__.py
@@ -5,11 +5,10 @@ This package contains logic to read and write LRF files.
 The LRF file format is documented at U{http://www.sven.de/librie/Librie/LrfFormat}.
 """
 
-from calibre.ebooks.lrf.pylrs.pylrs import Book as _Book
-from calibre.ebooks.lrf.pylrs.pylrs import TextBlock, Header, \
-                                             TextStyle, BlockStyle
-from calibre.ebooks.lrf.fonts import FONT_FILE_MAP
 from calibre.ebooks import ConversionError
+from calibre.ebooks.lrf.fonts import FONT_FILE_MAP
+from calibre.ebooks.lrf.pylrs.pylrs import BlockStyle, Header, TextBlock, TextStyle
+from calibre.ebooks.lrf.pylrs.pylrs import Book as _Book
 
 __docformat__ = "epytext"
 
diff --git a/src/calibre/ebooks/lrf/html/convert_from.py b/src/calibre/ebooks/lrf/html/convert_from.py
index bf6a7263ed..b0c6aa7351 100644
--- a/src/calibre/ebooks/lrf/html/convert_from.py
+++ b/src/calibre/ebooks/lrf/html/convert_from.py
@@ -12,23 +12,36 @@ from functools import partial
 from itertools import chain
 from math import ceil, floor
 
-from calibre import (
-    __appname__, entity_to_unicode, fit_image, force_unicode, preferred_encoding
-)
+from calibre import __appname__, entity_to_unicode, fit_image, force_unicode, preferred_encoding
 from calibre.constants import filesystem_encoding
 from calibre.devices.interface import DevicePlugin as Device
 from calibre.ebooks import ConversionError
-from calibre.ebooks.BeautifulSoup import (
-    BeautifulSoup, Comment, Declaration, NavigableString, ProcessingInstruction, Tag
-)
+from calibre.ebooks.BeautifulSoup import BeautifulSoup, Comment, Declaration, NavigableString, ProcessingInstruction, Tag
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.ebooks.lrf import Book
 from calibre.ebooks.lrf.html.color_map import lrs_color
 from calibre.ebooks.lrf.html.table import Table
 from calibre.ebooks.lrf.pylrs.pylrs import (
-    CR, BlockSpace, BookSetting, Canvas, CharButton, DropCaps, EmpLine, Image,
-    ImageBlock, ImageStream, Italic, JumpButton, LrsError, Paragraph, Plot,
-    RuledLine, Span, Sub, Sup, TextBlock
+    CR,
+    BlockSpace,
+    BookSetting,
+    Canvas,
+    CharButton,
+    DropCaps,
+    EmpLine,
+    Image,
+    ImageBlock,
+    ImageStream,
+    Italic,
+    JumpButton,
+    LrsError,
+    Paragraph,
+    Plot,
+    RuledLine,
+    Span,
+    Sub,
+    Sup,
+    TextBlock,
 )
 from calibre.ptempfile import PersistentTemporaryFile
 from polyglot.builtins import itervalues, string_or_bytes
diff --git a/src/calibre/ebooks/lrf/html/table.py b/src/calibre/ebooks/lrf/html/table.py
index de8c483830..8cf227c791 100644
--- a/src/calibre/ebooks/lrf/html/table.py
+++ b/src/calibre/ebooks/lrf/html/table.py
@@ -1,12 +1,13 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
-import math, sys, re, numbers
+import math
+import numbers
+import re
+import sys
 
 from calibre.ebooks.lrf.fonts import get_font
-from calibre.ebooks.lrf.pylrs.pylrs import TextBlock, Text, CR, Span, \
-                                             CharButton, Plot, Paragraph, \
-                                             LrsTextTag
-from polyglot.builtins import string_or_bytes, native_string_type
+from calibre.ebooks.lrf.pylrs.pylrs import CR, CharButton, LrsTextTag, Paragraph, Plot, Span, Text, TextBlock
+from polyglot.builtins import native_string_type, string_or_bytes
 
 
 def ceil(num):
diff --git a/src/calibre/ebooks/lrf/input.py b/src/calibre/ebooks/lrf/input.py
index d14def7d79..5d46a201be 100644
--- a/src/calibre/ebooks/lrf/input.py
+++ b/src/calibre/ebooks/lrf/input.py
@@ -8,6 +8,7 @@ __docformat__ = 'restructuredtext en'
 import operator
 import textwrap
 from copy import copy, deepcopy
+
 from lxml import etree
 
 from calibre import guess_type
diff --git a/src/calibre/ebooks/lrf/lrfparser.py b/src/calibre/ebooks/lrf/lrfparser.py
index 29675cc08a..44bf1f80f3 100644
--- a/src/calibre/ebooks/lrf/lrfparser.py
+++ b/src/calibre/ebooks/lrf/lrfparser.py
@@ -2,15 +2,19 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 ''''''
 
-import sys, array, os, re, codecs, logging
+import array
+import codecs
+import logging
+import os
+import re
+import sys
 from itertools import chain
 
 from calibre import setup_cli_handlers
+from calibre.ebooks.lrf.meta import LRFMetaFile
+from calibre.ebooks.lrf.objects import BookAttr, Font, PageTree, StyleObject, Text, TOCObject, get_object, ruby_tags
 from calibre.utils.config import OptionParser
 from calibre.utils.filenames import ascii_filename
-from calibre.ebooks.lrf.meta import LRFMetaFile
-from calibre.ebooks.lrf.objects import get_object, PageTree, StyleObject, \
-                                         Font, Text, TOCObject, BookAttr, ruby_tags
 from polyglot.builtins import itervalues
 
 
diff --git a/src/calibre/ebooks/lrf/lrs/convert_from.py b/src/calibre/ebooks/lrf/lrs/convert_from.py
index 94d8e215a9..f1fed2806c 100644
--- a/src/calibre/ebooks/lrf/lrs/convert_from.py
+++ b/src/calibre/ebooks/lrf/lrs/convert_from.py
@@ -9,15 +9,37 @@ import os
 import sys
 
 from calibre import setup_cli_handlers
-from calibre.ebooks.BeautifulSoup import (
-    BeautifulStoneSoup, CData, NavigableString, Tag
-)
+from calibre.ebooks.BeautifulSoup import BeautifulStoneSoup, CData, NavigableString, Tag
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.ebooks.lrf.pylrs.pylrs import (
-    CR, BlockStyle, Bold, Book, BookSetting, Canvas, CharButton, DropCaps, EmpLine,
-    Font, Footer, Header, Image, ImageBlock, ImageStream, Italic, JumpButton, Page,
-    PageStyle, Paragraph, Plot, RuledLine, Span, StyleDefault, Sub, Sup, TextBlock,
-    TextStyle
+    CR,
+    BlockStyle,
+    Bold,
+    Book,
+    BookSetting,
+    Canvas,
+    CharButton,
+    DropCaps,
+    EmpLine,
+    Font,
+    Footer,
+    Header,
+    Image,
+    ImageBlock,
+    ImageStream,
+    Italic,
+    JumpButton,
+    Page,
+    PageStyle,
+    Paragraph,
+    Plot,
+    RuledLine,
+    Span,
+    StyleDefault,
+    Sub,
+    Sup,
+    TextBlock,
+    TextStyle,
 )
 from calibre.utils.config import OptionParser
 from polyglot.builtins import string_or_bytes
diff --git a/src/calibre/ebooks/lrf/meta.py b/src/calibre/ebooks/lrf/meta.py
index b85a9dc78b..7893c66fb7 100644
--- a/src/calibre/ebooks/lrf/meta.py
+++ b/src/calibre/ebooks/lrf/meta.py
@@ -12,14 +12,18 @@ to get and set meta information. For example:
 >>> lrf.category = "History"
 """
 
-import io, struct, zlib, sys, os
-from shutil import copyfileobj
+import io
+import os
+import struct
+import sys
 import xml.dom.minidom as dom
+import zlib
 from functools import wraps
+from shutil import copyfileobj
 
 from calibre.ebooks.chardet import xml_to_unicode
-from calibre.utils.cleantext import clean_xml_chars
 from calibre.ebooks.metadata import MetaInformation, string_to_authors
+from calibre.utils.cleantext import clean_xml_chars
 from polyglot.builtins import string_or_bytes
 
 BYTE      = "<B"  #: Unsigned char little endian encoded in 1 byte
@@ -611,8 +615,8 @@ class LRFMetaFile:
 
 
 def option_parser():
-    from calibre.utils.config import OptionParser
     from calibre.constants import __appname__, __version__
+    from calibre.utils.config import OptionParser
     parser = OptionParser(usage=_('''%prog [options] mybook.lrf
 
 
diff --git a/src/calibre/ebooks/lrf/objects.py b/src/calibre/ebooks/lrf/objects.py
index c5c9a4b035..63f02b9d7f 100644
--- a/src/calibre/ebooks/lrf/objects.py
+++ b/src/calibre/ebooks/lrf/objects.py
@@ -1,9 +1,14 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
-import struct, array, zlib, io, collections, re
+import array
+import collections
+import io
+import re
+import struct
+import zlib
 
-from calibre.ebooks.lrf import LRFParseError, PRS500_PROFILE
 from calibre import entity_to_unicode, prepare_string_for_xml
+from calibre.ebooks.lrf import PRS500_PROFILE, LRFParseError
 from calibre.ebooks.lrf.tags import Tag
 
 ruby_tags = {
diff --git a/src/calibre/ebooks/lrf/pylrs/pylrf.py b/src/calibre/ebooks/lrf/pylrs/pylrf.py
index 91889b14ae..b27e3ca130 100644
--- a/src/calibre/ebooks/lrf/pylrs/pylrf.py
+++ b/src/calibre/ebooks/lrf/pylrs/pylrf.py
@@ -5,14 +5,15 @@
     pylrf.py -- very low level interface to create lrf files.  See pylrs for
     higher level interface that can use this module to render books to lrf.
 """
+import codecs
+import io
+import os
 import struct
 import zlib
-import io
-import codecs
-import os
+
+from polyglot.builtins import iteritems, string_or_bytes
 
 from .pylrfopt import tagListOptimizer
-from polyglot.builtins import iteritems, string_or_bytes
 
 PYLRF_VERSION = "1.0"
 
diff --git a/src/calibre/ebooks/lrf/pylrs/pylrs.py b/src/calibre/ebooks/lrf/pylrs/pylrs.py
index 2f011ec3ae..d110f90af1 100644
--- a/src/calibre/ebooks/lrf/pylrs/pylrs.py
+++ b/src/calibre/ebooks/lrf/pylrs/pylrs.py
@@ -36,23 +36,37 @@
 #                           Plot, Image (outside of ImageBlock),
 #                           EmpLine, EmpDots
 
-import os, re, codecs, operator, io
-from xml.sax.saxutils import escape
+import codecs
+import io
+import operator
+import os
+import re
 from datetime import date
-from xml.etree.ElementTree import Element, SubElement, ElementTree
+from xml.etree.ElementTree import Element, ElementTree, SubElement
+from xml.sax.saxutils import escape
 
-from .pylrf import (LrfWriter, LrfObject, LrfTag, LrfToc,
-        STREAM_COMPRESSED, LrfTagStream, LrfStreamBase, IMAGE_TYPE_ENCODING,
-        BINDING_DIRECTION_ENCODING, LINE_TYPE_ENCODING, LrfFileStream,
-        STREAM_FORCE_COMPRESSED)
 from calibre.utils.date import isoformat
 
+from .pylrf import (
+    BINDING_DIRECTION_ENCODING,
+    IMAGE_TYPE_ENCODING,
+    LINE_TYPE_ENCODING,
+    STREAM_COMPRESSED,
+    STREAM_FORCE_COMPRESSED,
+    LrfFileStream,
+    LrfObject,
+    LrfStreamBase,
+    LrfTag,
+    LrfTagStream,
+    LrfToc,
+    LrfWriter,
+)
+
 DEFAULT_SOURCE_ENCODING = "cp1252"      # default is us-windows character set
 DEFAULT_GENREADING      = "fs"          # default is yes to both lrf and lrs
 
-from calibre import __appname__, __version__
-from calibre import entity_to_unicode
-from polyglot.builtins import string_or_bytes, iteritems, native_string_type
+from calibre import __appname__, __version__, entity_to_unicode
+from polyglot.builtins import iteritems, native_string_type, string_or_bytes
 
 
 class LrsError(Exception):
diff --git a/src/calibre/ebooks/metadata/__init__.py b/src/calibre/ebooks/metadata/__init__.py
index 35ddd231a9..1a38a82b32 100644
--- a/src/calibre/ebooks/metadata/__init__.py
+++ b/src/calibre/ebooks/metadata/__init__.py
@@ -8,15 +8,16 @@ __docformat__ = 'restructuredtext en'
 """
 Provides abstraction for metadata reading.writing from a variety of ebook formats.
 """
-import os, sys, re
+import os
+import re
+import sys
 from contextlib import suppress
 
-from calibre import relpath, guess_type, prints, force_unicode
+from calibre import force_unicode, guess_type, prints, relpath
 from calibre.utils.config_base import tweaks
-from polyglot.builtins import iteritems, as_unicode
+from polyglot.builtins import as_unicode, iteritems
 from polyglot.urllib import quote, unquote, urlparse
 
-
 try:
     _author_pat = re.compile(tweaks['authors_split_regex'])
 except Exception:
diff --git a/src/calibre/ebooks/metadata/archive.py b/src/calibre/ebooks/metadata/archive.py
index 50b4750124..301d611894 100644
--- a/src/calibre/ebooks/metadata/archive.py
+++ b/src/calibre/ebooks/metadata/archive.py
@@ -193,8 +193,9 @@ def get_comic_book_info(d, mi, series_index='volume'):
         mi.comments = comments.strip()
     pubm, puby = d.get('publicationMonth', None), d.get('publicationYear', None)
     if puby is not None:
-        from calibre.utils.date import parse_only_date
         from datetime import date
+
+        from calibre.utils.date import parse_only_date
         try:
             dt = date(puby, 6 if pubm is None else pubm, 15)
             dt = parse_only_date(str(dt))
@@ -205,8 +206,9 @@ def get_comic_book_info(d, mi, series_index='volume'):
 
 def parse_comic_comment(comment, series_index='volume'):
     # See http://code.google.com/p/comicbookinfo/wiki/Example
-    from calibre.ebooks.metadata import MetaInformation
     import json
+
+    from calibre.ebooks.metadata import MetaInformation
     mi = MetaInformation(None, None)
     m = json.loads(comment)
     if isinstance(m, dict):
diff --git a/src/calibre/ebooks/metadata/author_mapper.py b/src/calibre/ebooks/metadata/author_mapper.py
index 9286f160f7..56643deecf 100644
--- a/src/calibre/ebooks/metadata/author_mapper.py
+++ b/src/calibre/ebooks/metadata/author_mapper.py
@@ -5,9 +5,9 @@
 import re
 from collections import deque
 
-from calibre.utils.icu import (
-    capitalize, lower, lower as icu_lower, upper, upper as icu_upper,
-)
+from calibre.utils.icu import capitalize, lower, upper
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 
 
 def cap_author_token(token):
diff --git a/src/calibre/ebooks/metadata/book/base.py b/src/calibre/ebooks/metadata/book/base.py
index b37756bb8b..ce85f7dadd 100644
--- a/src/calibre/ebooks/metadata/book/base.py
+++ b/src/calibre/ebooks/metadata/book/base.py
@@ -10,12 +10,10 @@ import traceback
 
 from calibre import prints
 from calibre.constants import DEBUG
-from calibre.ebooks.metadata.book import (
-    ALL_METADATA_FIELDS, SC_COPYABLE_FIELDS, SC_FIELDS_COPY_NOT_NULL,
-    STANDARD_METADATA_FIELDS, TOP_LEVEL_IDENTIFIERS,
-)
+from calibre.ebooks.metadata.book import ALL_METADATA_FIELDS, SC_COPYABLE_FIELDS, SC_FIELDS_COPY_NOT_NULL, STANDARD_METADATA_FIELDS, TOP_LEVEL_IDENTIFIERS
 from calibre.library.field_metadata import FieldMetadata
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 from calibre.utils.localization import ngettext
 from polyglot.builtins import iteritems, string_or_bytes
 
diff --git a/src/calibre/ebooks/metadata/book/formatter.py b/src/calibre/ebooks/metadata/book/formatter.py
index 5d651f7eef..7abb794987 100644
--- a/src/calibre/ebooks/metadata/book/formatter.py
+++ b/src/calibre/ebooks/metadata/book/formatter.py
@@ -4,11 +4,11 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from calibre.ebooks.metadata.book import TOP_LEVEL_IDENTIFIERS, ALL_METADATA_FIELDS
-
-from calibre.utils.formatter import TemplateFormatter
 from numbers import Number
 
+from calibre.ebooks.metadata.book import ALL_METADATA_FIELDS, TOP_LEVEL_IDENTIFIERS
+from calibre.utils.formatter import TemplateFormatter
+
 
 class SafeFormat(TemplateFormatter):
 
diff --git a/src/calibre/ebooks/metadata/book/json_codec.py b/src/calibre/ebooks/metadata/book/json_codec.py
index cc48aeb2c6..093ec68147 100644
--- a/src/calibre/ebooks/metadata/book/json_codec.py
+++ b/src/calibre/ebooks/metadata/book/json_codec.py
@@ -4,15 +4,16 @@ Created on 4 Jun 2010
 @author: charles
 '''
 
-import json, traceback
+import json
+import traceback
 from datetime import datetime, time
 
-from calibre.ebooks.metadata.book import SERIALIZABLE_FIELDS
-from calibre.constants import filesystem_encoding, preferred_encoding
-from calibre.library.field_metadata import FieldMetadata
 from calibre import isbytestring
-from polyglot.builtins import iteritems, itervalues, as_bytes
+from calibre.constants import filesystem_encoding, preferred_encoding
+from calibre.ebooks.metadata.book import SERIALIZABLE_FIELDS
+from calibre.library.field_metadata import FieldMetadata
 from polyglot.binary import as_base64_unicode, from_base64_bytes
+from polyglot.builtins import as_bytes, iteritems, itervalues
 
 # Translate datetimes to and from strings. The string form is the datetime in
 # UTC. The returned date is also UTC
@@ -29,7 +30,7 @@ def string_to_datetime(src):
 
 
 def datetime_to_string(dateval):
-    from calibre.utils.date import isoformat, UNDEFINED_DATE, local_tz
+    from calibre.utils.date import UNDEFINED_DATE, isoformat, local_tz
     if dateval is None:
         return "None"
     if not isinstance(dateval, datetime):
diff --git a/src/calibre/ebooks/metadata/book/render.py b/src/calibre/ebooks/metadata/book/render.py
index 14608452a1..e973b3aeb9 100644
--- a/src/calibre/ebooks/metadata/book/render.py
+++ b/src/calibre/ebooks/metadata/book/render.py
@@ -12,9 +12,7 @@ from calibre import force_unicode, prepare_string_for_xml
 from calibre.constants import filesystem_encoding
 from calibre.db.constants import DATA_DIR_NAME
 from calibre.ebooks.metadata import fmt_sidx, rating_to_stars
-from calibre.ebooks.metadata.search_internet import (
-    DEFAULT_AUTHOR_SOURCE, name_for, qquote, url_for_author_search, url_for_book_search,
-)
+from calibre.ebooks.metadata.search_internet import DEFAULT_AUTHOR_SOURCE, name_for, qquote, url_for_author_search, url_for_book_search
 from calibre.ebooks.metadata.sources.identify import urls_from_identifiers
 from calibre.library.comments import comments_to_html, markdown
 from calibre.utils.date import format_date, is_date_undefined
diff --git a/src/calibre/ebooks/metadata/book/serialize.py b/src/calibre/ebooks/metadata/book/serialize.py
index 4e12a9437a..c8edd55edd 100644
--- a/src/calibre/ebooks/metadata/book/serialize.py
+++ b/src/calibre/ebooks/metadata/book/serialize.py
@@ -6,8 +6,8 @@ from calibre.constants import preferred_encoding
 from calibre.ebooks.metadata.book import SERIALIZABLE_FIELDS
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.utils.imghdr import what
-from polyglot.builtins import iteritems
 from polyglot.binary import as_base64_unicode
+from polyglot.builtins import iteritems
 
 
 def ensure_unicode(obj, enc=preferred_encoding):
diff --git a/src/calibre/ebooks/metadata/cli.py b/src/calibre/ebooks/metadata/cli.py
index fb6a1ed0a6..e1f913a0ce 100644
--- a/src/calibre/ebooks/metadata/cli.py
+++ b/src/calibre/ebooks/metadata/cli.py
@@ -5,15 +5,16 @@ __docformat__ = 'restructuredtext en'
 '''
 ebook-meta
 '''
-import sys, os, unicodedata
+import os
+import sys
+import unicodedata
 
-from calibre.utils.config import StringConfig
-from calibre.customize.ui import metadata_readers, metadata_writers, force_identifiers
-from calibre.ebooks.metadata.meta import get_metadata, set_metadata
-from calibre.ebooks.metadata import string_to_authors, authors_to_sort_string, \
-                    title_sort, MetaInformation
-from calibre.ebooks.lrf.meta import LRFMetaFile
 from calibre import prints
+from calibre.customize.ui import force_identifiers, metadata_readers, metadata_writers
+from calibre.ebooks.lrf.meta import LRFMetaFile
+from calibre.ebooks.metadata import MetaInformation, authors_to_sort_string, string_to_authors, title_sort
+from calibre.ebooks.metadata.meta import get_metadata, set_metadata
+from calibre.utils.config import StringConfig
 from calibre.utils.date import parse_date
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/ebooks/metadata/docx.py b/src/calibre/ebooks/metadata/docx.py
index 97d4c37f76..00d0e8807a 100644
--- a/src/calibre/ebooks/metadata/docx.py
+++ b/src/calibre/ebooks/metadata/docx.py
@@ -8,9 +8,9 @@ __docformat__ = 'restructuredtext en'
 from io import BytesIO
 
 from calibre.ebooks.docx.container import DOCX
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.ebooks.docx.writer.container import update_doc_props, xml2str
 from calibre.utils.imghdr import identify
+from calibre.utils.xml_parse import safe_xml_fromstring
 
 
 def get_cover(docx):
diff --git a/src/calibre/ebooks/metadata/epub.py b/src/calibre/ebooks/metadata/epub.py
index 63722651cf..1f3141b113 100644
--- a/src/calibre/ebooks/metadata/epub.py
+++ b/src/calibre/ebooks/metadata/epub.py
@@ -13,13 +13,12 @@ import posixpath
 from contextlib import closing
 
 from calibre import CurrentDir
-from calibre.ebooks.metadata.opf import (
-    get_metadata as get_metadata_from_opf, set_metadata as set_metadata_opf
-)
+from calibre.ebooks.metadata.opf import get_metadata as get_metadata_from_opf
+from calibre.ebooks.metadata.opf import set_metadata as set_metadata_opf
 from calibre.ebooks.metadata.opf2 import OPF
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.localunzip import LocalZipFile
+from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.utils.zipfile import BadZipfile, ZipFile, safe_replace
 
 
diff --git a/src/calibre/ebooks/metadata/ereader.py b/src/calibre/ebooks/metadata/ereader.py
index 339ff4d919..2ffe6685ab 100644
--- a/src/calibre/ebooks/metadata/ereader.py
+++ b/src/calibre/ebooks/metadata/ereader.py
@@ -9,11 +9,9 @@ __docformat__ = 'restructuredtext en'
 import re
 import struct
 
-from calibre.ebooks.metadata import MetaInformation
-from calibre.ebooks.metadata import authors_to_string
+from calibre.ebooks.metadata import MetaInformation, authors_to_string
 from calibre.ebooks.pdb.ereader.reader132 import HeaderRecord
-from calibre.ebooks.pdb.header import PdbHeaderBuilder
-from calibre.ebooks.pdb.header import PdbHeaderReader
+from calibre.ebooks.pdb.header import PdbHeaderBuilder, PdbHeaderReader
 
 
 def get_cover(pheader, eheader):
diff --git a/src/calibre/ebooks/metadata/fb2.py b/src/calibre/ebooks/metadata/fb2.py
index 04e11d5e1f..bf0b17bc70 100644
--- a/src/calibre/ebooks/metadata/fb2.py
+++ b/src/calibre/ebooks/metadata/fb2.py
@@ -6,23 +6,22 @@ __copyright__ = '2011, Roman Mukhin <ramses_ru at hotmail.com>, '\
                 '2008, Anatoly Shipitsin <norguhtar at gmail.com>'
 '''Read meta information from fb2 files'''
 
-import os, random
+import os
+import random
 from functools import partial
 from string import ascii_letters, digits
 
 from lxml import etree
 
-from calibre import strftime
+from calibre import force_unicode, guess_all_extensions, guess_type, prints, strftime
+from calibre.ebooks.chardet import xml_to_unicode
+from calibre.ebooks.metadata import MetaInformation, check_isbn
 from calibre.utils.date import parse_only_date
 from calibre.utils.img import save_cover_data_to
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.utils.imghdr import identify
-from calibre import guess_type, guess_all_extensions, prints, force_unicode
-from calibre.ebooks.metadata import MetaInformation, check_isbn
-from calibre.ebooks.chardet import xml_to_unicode
+from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.binary import as_base64_unicode
 
-
 NAMESPACES = {
     'fb2'   :   'http://www.gribuser.ru/xml/fictionbook/2.0',
     'fb21'  :   'http://www.gribuser.ru/xml/fictionbook/2.1',
@@ -89,7 +88,7 @@ class Context:
 
 
 def get_fb2_data(stream):
-    from calibre.utils.zipfile import ZipFile, BadZipfile
+    from calibre.utils.zipfile import BadZipfile, ZipFile
     pos = stream.tell()
     try:
         zf = ZipFile(stream)
diff --git a/src/calibre/ebooks/metadata/haodoo.py b/src/calibre/ebooks/metadata/haodoo.py
index f446bd66ac..e602ebf213 100644
--- a/src/calibre/ebooks/metadata/haodoo.py
+++ b/src/calibre/ebooks/metadata/haodoo.py
@@ -6,8 +6,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kan-Ru Chen <kanru@kanru.info>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.ebooks.pdb.header import PdbHeaderReader
 from calibre.ebooks.pdb.haodoo.reader import Reader
+from calibre.ebooks.pdb.header import PdbHeaderReader
 
 
 def get_metadata(stream, extract_cover=True):
diff --git a/src/calibre/ebooks/metadata/html.py b/src/calibre/ebooks/metadata/html.py
index 14cb98bbce..00a4f40e42 100644
--- a/src/calibre/ebooks/metadata/html.py
+++ b/src/calibre/ebooks/metadata/html.py
@@ -9,16 +9,16 @@ Try to read metadata from an HTML file.
 
 import re
 import unittest
-
 from collections import defaultdict
+
 from html5_parser import parse
 from lxml.etree import Comment
 
-from calibre.ebooks.metadata import string_to_authors, authors_to_string
-from calibre.ebooks.metadata.book.base import Metadata
+from calibre import isbytestring, replace_entities
 from calibre.ebooks.chardet import xml_to_unicode
-from calibre import replace_entities, isbytestring
-from calibre.utils.date import parse_date, is_date_undefined
+from calibre.ebooks.metadata import authors_to_string, string_to_authors
+from calibre.ebooks.metadata.book.base import Metadata
+from calibre.utils.date import is_date_undefined, parse_date
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/metadata/kdl.py b/src/calibre/ebooks/metadata/kdl.py
index 727cb94a81..37acbb60b3 100644
--- a/src/calibre/ebooks/metadata/kdl.py
+++ b/src/calibre/ebooks/metadata/kdl.py
@@ -5,14 +5,15 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, socket
+import re
+import socket
 
 from mechanize import URLError
 
-from calibre.ebooks.metadata.book.base import Metadata
 from calibre import browser
 from calibre.ebooks.BeautifulSoup import BeautifulSoup
 from calibre.ebooks.chardet import xml_to_unicode
+from calibre.ebooks.metadata.book.base import Metadata
 from polyglot.builtins import codepoint_to_chr
 from polyglot.urllib import parse_qs, quote_plus
 
diff --git a/src/calibre/ebooks/metadata/kfx.py b/src/calibre/ebooks/metadata/kfx.py
index 1afae122d2..992cd53048 100644
--- a/src/calibre/ebooks/metadata/kfx.py
+++ b/src/calibre/ebooks/metadata/kfx.py
@@ -5,7 +5,9 @@
 # Based on work of John Howell reversing the KFX format
 # https://www.mobileread.com/forums/showpost.php?p=3176029&postcount=89
 
-import struct, sys, re
+import re
+import struct
+import sys
 from collections import defaultdict
 
 from calibre.ebooks.metadata.book.base import Metadata
@@ -13,8 +15,8 @@ from calibre.ebooks.mobi.utils import decint
 from calibre.utils.cleantext import clean_xml_chars
 from calibre.utils.config_base import tweaks
 from calibre.utils.date import parse_only_date
-from calibre.utils.localization import canonicalize_lang
 from calibre.utils.imghdr import identify
+from calibre.utils.localization import canonicalize_lang
 from polyglot.binary import as_base64_bytes, from_base64_bytes
 
 
diff --git a/src/calibre/ebooks/metadata/meta.py b/src/calibre/ebooks/metadata/meta.py
index f7a9cfc412..1499eb69c6 100644
--- a/src/calibre/ebooks/metadata/meta.py
+++ b/src/calibre/ebooks/metadata/meta.py
@@ -1,14 +1,17 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, regex, collections
+import collections
+import os
+
+import regex
 
-from calibre.utils.config import prefs
-from calibre.constants import filesystem_encoding
-from calibre.ebooks.metadata.opf2 import OPF
 from calibre import isbytestring
+from calibre.constants import filesystem_encoding
 from calibre.customize.ui import get_file_type_metadata, set_file_type_metadata
 from calibre.ebooks.metadata import MetaInformation, string_to_authors
+from calibre.ebooks.metadata.opf2 import OPF
+from calibre.utils.config import prefs
 
 # The priorities for loading metadata from different file types
 # Higher values should be used to update metadata from lower values
diff --git a/src/calibre/ebooks/metadata/mobi.py b/src/calibre/ebooks/metadata/mobi.py
index 2ca77b77cd..dbba75145a 100644
--- a/src/calibre/ebooks/metadata/mobi.py
+++ b/src/calibre/ebooks/metadata/mobi.py
@@ -16,7 +16,6 @@ from calibre.utils.imghdr import what
 from calibre.utils.localization import canonicalize_lang, lang_as_iso639_1
 from polyglot.builtins import codepoint_to_chr
 
-
 '''
 Retrieve and modify in-place Mobipocket book metadata.
 '''
@@ -478,12 +477,12 @@ def set_metadata(stream, mi):
 
 
 def get_metadata(stream):
+    from calibre import CurrentDir
     from calibre.ebooks.metadata import MetaInformation
-    from calibre.ptempfile import TemporaryDirectory
     from calibre.ebooks.mobi.reader.headers import MetadataHeader
     from calibre.ebooks.mobi.reader.mobi6 import MobiReader
+    from calibre.ptempfile import TemporaryDirectory
     from calibre.utils.img import save_cover_data_to
-    from calibre import CurrentDir
 
     stream.seek(0)
     try:
diff --git a/src/calibre/ebooks/metadata/odt.py b/src/calibre/ebooks/metadata/odt.py
index 0b1e3d7ffa..932a088f05 100644
--- a/src/calibre/ebooks/metadata/odt.py
+++ b/src/calibre/ebooks/metadata/odt.py
@@ -25,17 +25,16 @@ import os
 import re
 
 from lxml.etree import fromstring, tostring
+from odf.draw import Frame as odFrame
+from odf.draw import Image as odImage
+from odf.namespaces import DCNS, METANS, OFFICENS
+from odf.opendocument import load as odLoad
 
-from calibre.ebooks.metadata import (
-    MetaInformation, authors_to_string, check_isbn, string_to_authors
-)
+from calibre.ebooks.metadata import MetaInformation, authors_to_string, check_isbn, string_to_authors
 from calibre.utils.date import isoformat, parse_date
 from calibre.utils.imghdr import identify
 from calibre.utils.localization import canonicalize_lang, lang_as_iso639_1
 from calibre.utils.zipfile import ZipFile, safe_replace
-from odf.draw import Frame as odFrame, Image as odImage
-from odf.namespaces import DCNS, METANS, OFFICENS
-from odf.opendocument import load as odLoad
 from polyglot.builtins import as_unicode
 
 fields = {
diff --git a/src/calibre/ebooks/metadata/opf.py b/src/calibre/ebooks/metadata/opf.py
index 7e24154ad9..090d966e68 100644
--- a/src/calibre/ebooks/metadata/opf.py
+++ b/src/calibre/ebooks/metadata/opf.py
@@ -4,10 +4,10 @@
 
 from lxml import etree
 
+from calibre.ebooks.metadata import MetaInformation
 from calibre.ebooks.metadata.opf2 import OPF, pretty_print
 from calibre.ebooks.metadata.opf3 import apply_metadata, read_metadata
-from calibre.ebooks.metadata.utils import parse_opf, normalize_languages, create_manifest_item, parse_opf_version
-from calibre.ebooks.metadata import MetaInformation
+from calibre.ebooks.metadata.utils import create_manifest_item, normalize_languages, parse_opf, parse_opf_version
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/metadata/opf2.py b/src/calibre/ebooks/metadata/opf2.py
index 58b9928bf4..6a5eddf387 100644
--- a/src/calibre/ebooks/metadata/opf2.py
+++ b/src/calibre/ebooks/metadata/opf2.py
@@ -18,6 +18,7 @@ import re
 import sys
 import uuid
 from contextlib import suppress
+
 from lxml import etree
 
 from calibre import guess_type, prints
@@ -26,11 +27,13 @@ from calibre.ebooks import escape_xpath_attr
 from calibre.ebooks.metadata import MetaInformation, check_isbn, string_to_authors
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.toc import TOC
-from calibre.ebooks.metadata.utils import parse_opf, pretty_print_opf as _pretty_print
+from calibre.ebooks.metadata.utils import parse_opf
+from calibre.ebooks.metadata.utils import pretty_print_opf as _pretty_print
 from calibre.utils.cleantext import clean_ascii_chars, clean_xml_chars
 from calibre.utils.config import tweaks
 from calibre.utils.date import isoformat, parse_date
-from calibre.utils.icu import lower as icu_lower, upper as icu_upper
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 from calibre.utils.localization import canonicalize_lang, get_lang
 from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.builtins import iteritems
@@ -520,9 +523,7 @@ class TitleSortField(MetadataField):
 
 
 def serialize_user_metadata(metadata_elem, all_user_metadata, tail='\n'+(' '*8)):
-    from calibre.ebooks.metadata.book.json_codec import (
-        encode_is_multiple, object_to_unicode,
-    )
+    from calibre.ebooks.metadata.book.json_codec import encode_is_multiple, object_to_unicode
     from calibre.utils.config import to_json
 
     for name, fm in all_user_metadata.items():
@@ -1619,6 +1620,7 @@ class OPFCreator(Metadata):
 
 def metadata_to_opf(mi, as_string=True, default_lang=None):
     import textwrap
+
     from lxml import etree
 
     from calibre.ebooks.oeb.base import DC, OPF
diff --git a/src/calibre/ebooks/metadata/opf3.py b/src/calibre/ebooks/metadata/opf3.py
index 98f3f4a31b..1f44642ab7 100644
--- a/src/calibre/ebooks/metadata/opf3.py
+++ b/src/calibre/ebooks/metadata/opf3.py
@@ -7,27 +7,19 @@ import re
 from collections import defaultdict, namedtuple
 from contextlib import suppress
 from functools import wraps
-from lxml import etree
 from operator import attrgetter
 
+from lxml import etree
+
 from calibre import prints
-from calibre.ebooks.metadata import (
-    authors_to_string, check_isbn, fmt_sidx, string_to_authors
-)
+from calibre.ebooks.metadata import authors_to_string, check_isbn, fmt_sidx, string_to_authors
 from calibre.ebooks.metadata.book.base import Metadata
-from calibre.ebooks.metadata.book.json_codec import (
-    decode_is_multiple, encode_is_multiple, object_to_unicode
-)
-from calibre.ebooks.metadata.utils import (
-    create_manifest_item, ensure_unique, normalize_languages, parse_opf,
-    pretty_print_opf
-)
+from calibre.ebooks.metadata.book.json_codec import decode_is_multiple, encode_is_multiple, object_to_unicode
+from calibre.ebooks.metadata.utils import create_manifest_item, ensure_unique, normalize_languages, parse_opf, pretty_print_opf
 from calibre.ebooks.oeb.base import DC, OPF, OPF2_NSMAP
 from calibre.utils.config import from_json, to_json
-from calibre.utils.date import (
-    fix_only_date, is_date_undefined, isoformat, parse_date as parse_date_, utcnow,
-    w3cdtf
-)
+from calibre.utils.date import fix_only_date, is_date_undefined, isoformat, utcnow, w3cdtf
+from calibre.utils.date import parse_date as parse_date_
 from calibre.utils.iso8601 import parse_iso8601
 from calibre.utils.localization import canonicalize_lang
 from polyglot.builtins import iteritems
diff --git a/src/calibre/ebooks/metadata/opf3_test.py b/src/calibre/ebooks/metadata/opf3_test.py
index db06ad5f78..94be1cb287 100644
--- a/src/calibre/ebooks/metadata/opf3_test.py
+++ b/src/calibre/ebooks/metadata/opf3_test.py
@@ -9,15 +9,52 @@ from io import BytesIO
 from calibre.ebooks.metadata.book import ALL_METADATA_FIELDS
 from calibre.ebooks.metadata.opf2 import OPF
 from calibre.ebooks.metadata.opf3 import (
-    CALIBRE_PREFIX, Author, XPath, apply_metadata, ensure_is_only_raster_cover,
-    ensure_prefix, expand_prefix, parse_prefixes, read_authors, read_book_producers,
-    read_comments, read_identifiers, read_languages, read_last_modified, read_link_maps,
-    read_metadata, read_prefixes, read_pubdate, read_publisher, read_raster_cover,
-    read_rating, read_refines, read_series, read_tags, read_timestamp, read_title,
-    read_title_sort, read_user_categories, read_user_metadata, reserved_prefixes,
-    set_application_id, set_authors, set_book_producers, set_comments, set_identifiers,
-    set_languages, set_link_maps, set_pubdate, set_publisher, set_rating, set_series,
-    set_tags, set_timestamp, set_title, set_user_categories, set_user_metadata,
+    CALIBRE_PREFIX,
+    Author,
+    XPath,
+    apply_metadata,
+    ensure_is_only_raster_cover,
+    ensure_prefix,
+    expand_prefix,
+    parse_prefixes,
+    read_authors,
+    read_book_producers,
+    read_comments,
+    read_identifiers,
+    read_languages,
+    read_last_modified,
+    read_link_maps,
+    read_metadata,
+    read_prefixes,
+    read_pubdate,
+    read_publisher,
+    read_raster_cover,
+    read_rating,
+    read_refines,
+    read_series,
+    read_tags,
+    read_timestamp,
+    read_title,
+    read_title_sort,
+    read_user_categories,
+    read_user_metadata,
+    reserved_prefixes,
+    set_application_id,
+    set_authors,
+    set_book_producers,
+    set_comments,
+    set_identifiers,
+    set_languages,
+    set_link_maps,
+    set_pubdate,
+    set_publisher,
+    set_rating,
+    set_series,
+    set_tags,
+    set_timestamp,
+    set_title,
+    set_user_categories,
+    set_user_metadata,
 )
 
 # This import is needed to prevent a test from running slowly
diff --git a/src/calibre/ebooks/metadata/opf_2_to_3.py b/src/calibre/ebooks/metadata/opf_2_to_3.py
index fda4760db8..c51030345a 100644
--- a/src/calibre/ebooks/metadata/opf_2_to_3.py
+++ b/src/calibre/ebooks/metadata/opf_2_to_3.py
@@ -5,10 +5,24 @@
 from lxml import etree
 
 from calibre.ebooks.metadata.opf3 import (
-    DC, OPF, XPath, create_rating, create_series, create_timestamp,
-    encode_is_multiple, ensure_id, normalize_whitespace, parse_date, read_prefixes,
-    read_refines, read_user_metadata2, refdef, remove_element, set_last_modified,
-    set_refines, set_user_metadata3
+    DC,
+    OPF,
+    XPath,
+    create_rating,
+    create_series,
+    create_timestamp,
+    encode_is_multiple,
+    ensure_id,
+    normalize_whitespace,
+    parse_date,
+    read_prefixes,
+    read_refines,
+    read_user_metadata2,
+    refdef,
+    remove_element,
+    set_last_modified,
+    set_refines,
+    set_user_metadata3,
 )
 from calibre.ebooks.metadata.utils import parse_opf, pretty_print_opf
 from polyglot.builtins import itervalues
diff --git a/src/calibre/ebooks/metadata/pdb.py b/src/calibre/ebooks/metadata/pdb.py
index 4ab2130fd1..783cd77bbe 100644
--- a/src/calibre/ebooks/metadata/pdb.py
+++ b/src/calibre/ebooks/metadata/pdb.py
@@ -9,10 +9,10 @@ __docformat__ = 'restructuredtext en'
 import re
 
 from calibre.ebooks.metadata import MetaInformation
-from calibre.ebooks.pdb.header import PdbHeaderReader
 from calibre.ebooks.metadata.ereader import get_metadata as get_eReader
-from calibre.ebooks.metadata.plucker import get_metadata as get_plucker
 from calibre.ebooks.metadata.haodoo import get_metadata as get_Haodoo
+from calibre.ebooks.metadata.plucker import get_metadata as get_plucker
+from calibre.ebooks.pdb.header import PdbHeaderReader
 
 MREADER = {
     'PNPdPPrs' : get_eReader,
diff --git a/src/calibre/ebooks/metadata/pdf.py b/src/calibre/ebooks/metadata/pdf.py
index 93ff67ad8b..e8897e3d8a 100644
--- a/src/calibre/ebooks/metadata/pdf.py
+++ b/src/calibre/ebooks/metadata/pdf.py
@@ -2,15 +2,17 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 '''Read meta information from PDF files'''
 
-import os, subprocess, shutil, re
+import os
+import re
+import shutil
+import subprocess
 from functools import partial
 
 from calibre import prints
 from calibre.constants import iswindows
+from calibre.ebooks.metadata import MetaInformation, check_doi, check_isbn, string_to_authors
 from calibre.ptempfile import TemporaryDirectory
-from calibre.ebooks.metadata import (
-    MetaInformation, string_to_authors, check_isbn, check_doi)
-from calibre.utils.ipc.simple_worker import fork_job, WorkerError
+from calibre.utils.ipc.simple_worker import WorkerError, fork_job
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/metadata/plucker.py b/src/calibre/ebooks/metadata/plucker.py
index 4fedecb0f4..e478809059 100644
--- a/src/calibre/ebooks/metadata/plucker.py
+++ b/src/calibre/ebooks/metadata/plucker.py
@@ -11,8 +11,7 @@ from datetime import datetime
 
 from calibre.ebooks.metadata import MetaInformation
 from calibre.ebooks.pdb.header import PdbHeaderReader
-from calibre.ebooks.pdb.plucker.reader import SectionHeader, DATATYPE_METADATA, \
-    MIBNUM_TO_NAME
+from calibre.ebooks.pdb.plucker.reader import DATATYPE_METADATA, MIBNUM_TO_NAME, SectionHeader
 
 
 def get_metadata(stream, extract_cover=True):
diff --git a/src/calibre/ebooks/metadata/pml.py b/src/calibre/ebooks/metadata/pml.py
index b9ebb98f8f..db33a946d5 100644
--- a/src/calibre/ebooks/metadata/pml.py
+++ b/src/calibre/ebooks/metadata/pml.py
@@ -7,14 +7,14 @@ Read meta information from TXT files
 '''
 
 
-import os
 import glob
+import os
 import re
 
+from calibre import prepare_string_for_xml
 from calibre.ebooks.metadata import MetaInformation
 from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.zipfile import ZipFile
-from calibre import prepare_string_for_xml
 
 
 def get_metadata(stream, extract_cover=True):
diff --git a/src/calibre/ebooks/metadata/rb.py b/src/calibre/ebooks/metadata/rb.py
index 4140ab3c55..b19a995346 100644
--- a/src/calibre/ebooks/metadata/rb.py
+++ b/src/calibre/ebooks/metadata/rb.py
@@ -2,7 +2,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Ashish Kulkarni <kulkarni.ashish@gmail.com>'
 '''Read meta information from RB files'''
 
-import sys, struct
+import struct
+import sys
 
 from calibre import prints
 from calibre.ebooks.metadata import MetaInformation, string_to_authors
diff --git a/src/calibre/ebooks/metadata/rtf.py b/src/calibre/ebooks/metadata/rtf.py
index 103bc35746..07af613fa2 100644
--- a/src/calibre/ebooks/metadata/rtf.py
+++ b/src/calibre/ebooks/metadata/rtf.py
@@ -10,7 +10,7 @@ import re
 
 from calibre import force_unicode
 from calibre.ebooks.metadata import MetaInformation
-from polyglot.builtins import codepoint_to_chr, string_or_bytes, int_to_byte
+from polyglot.builtins import codepoint_to_chr, int_to_byte, string_or_bytes
 
 title_pat    = re.compile(br'\{\\info.*?\{\\title(.*?)(?<!\\)\}', re.DOTALL)
 author_pat   = re.compile(br'\{\\info.*?\{\\author(.*?)(?<!\\)\}', re.DOTALL)
@@ -231,6 +231,7 @@ def set_metadata(stream, options):
 def find_tests():
     import unittest
     from io import BytesIO
+
     from calibre.ebooks.metadata.book.base import Metadata
 
     class Test(unittest.TestCase):
diff --git a/src/calibre/ebooks/metadata/snb.py b/src/calibre/ebooks/metadata/snb.py
index b17a689bd2..3c5593b3c5 100644
--- a/src/calibre/ebooks/metadata/snb.py
+++ b/src/calibre/ebooks/metadata/snb.py
@@ -4,8 +4,9 @@
 __license__   = 'GPL v3'
 __copyright__ = '2010, Li Fanxi <lifanxi@freemindworld.com>'
 
-import os
 import io
+import os
+
 from calibre.ebooks.metadata import MetaInformation
 from calibre.ebooks.snb.snbfile import SNBFile
 from calibre.utils.xml_parse import safe_xml_fromstring
diff --git a/src/calibre/ebooks/metadata/sources/amazon.py b/src/calibre/ebooks/metadata/sources/amazon.py
index bca6926c8d..4db563e676 100644
--- a/src/calibre/ebooks/metadata/sources/amazon.py
+++ b/src/calibre/ebooks/metadata/sources/amazon.py
@@ -1755,10 +1755,7 @@ class Amazon(Source):
 def manual_tests(domain, **kw):  # {{{
     # To run these test use:
     # calibre-debug -c "from calibre.ebooks.metadata.sources.amazon import *; manual_tests('com')"
-    from calibre.ebooks.metadata.sources.test import (
-        authors_test, comments_test, isbn_test, series_test, test_identify_plugin,
-        title_test,
-    )
+    from calibre.ebooks.metadata.sources.test import authors_test, comments_test, isbn_test, series_test, test_identify_plugin, title_test
     all_tests = {}
     all_tests['com'] = [  # {{{
         (   # Paperback with series
diff --git a/src/calibre/ebooks/metadata/sources/base.py b/src/calibre/ebooks/metadata/sources/base.py
index 562d9b7ea6..62148400f8 100644
--- a/src/calibre/ebooks/metadata/sources/base.py
+++ b/src/calibre/ebooks/metadata/sources/base.py
@@ -6,7 +6,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, threading
+import re
+import threading
 from functools import total_ordering
 
 from calibre import browser, random_user_agent
@@ -14,11 +15,11 @@ from calibre.customize import Plugin
 from calibre.ebooks.metadata import check_isbn
 from calibre.ebooks.metadata.author_mapper import cap_author_token
 from calibre.utils.localization import canonicalize_lang, get_lang
-from polyglot.builtins import iteritems, cmp
+from polyglot.builtins import cmp, iteritems
 
 
 def create_log(ostream=None):
-    from calibre.utils.logging import ThreadSafeLog, FileStream
+    from calibre.utils.logging import FileStream, ThreadSafeLog
     log = ThreadSafeLog(level=ThreadSafeLog.DEBUG)
     log.outputs = [FileStream(ostream)]
     return log
@@ -441,8 +442,8 @@ class Source(Plugin):
         if not urls:
             log('No images found for, title: %r and authors: %r'%(title, authors))
             return
-        from threading import Thread
         import time
+        from threading import Thread
         if prefs_name:
             urls = urls[:self.prefs[prefs_name]]
         if get_best_cover:
diff --git a/src/calibre/ebooks/metadata/sources/big_book_search.py b/src/calibre/ebooks/metadata/sources/big_book_search.py
index 68d5eed464..78305483e7 100644
--- a/src/calibre/ebooks/metadata/sources/big_book_search.py
+++ b/src/calibre/ebooks/metadata/sources/big_book_search.py
@@ -6,11 +6,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.ebooks.metadata.sources.base import Source, Option
+from calibre.ebooks.metadata.sources.base import Option, Source
 
 
 def get_urls(br, tokens):
     from urllib.parse import quote_plus
+
     from html5_parser import parse
     escaped = (quote_plus(x) for x in tokens if x and x.strip())
     q = '+'.join(escaped)
@@ -45,8 +46,9 @@ class BigBookSearch(Source):
 
 
 def test():
-    from calibre import browser
     import pprint
+
+    from calibre import browser
     br = browser()
     urls = get_urls(br, ['consider', 'phlebas', 'banks'])
     pprint.pprint(urls)
diff --git a/src/calibre/ebooks/metadata/sources/cli.py b/src/calibre/ebooks/metadata/sources/cli.py
index bd37f57a2e..8d191209d3 100644
--- a/src/calibre/ebooks/metadata/sources/cli.py
+++ b/src/calibre/ebooks/metadata/sources/cli.py
@@ -11,14 +11,14 @@ from threading import Event
 
 from calibre import prints
 from calibre.customize.ui import all_metadata_plugins
-from calibre.utils.config import OptionParser
-from calibre.utils.img import save_cover_data_to
 from calibre.ebooks.metadata import string_to_authors
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
 from calibre.ebooks.metadata.sources.base import create_log
-from calibre.ebooks.metadata.sources.identify import identify
 from calibre.ebooks.metadata.sources.covers import download_cover
+from calibre.ebooks.metadata.sources.identify import identify
 from calibre.ebooks.metadata.sources.update import patch_plugins
+from calibre.utils.config import OptionParser
+from calibre.utils.img import save_cover_data_to
 
 
 def option_parser():
diff --git a/src/calibre/ebooks/metadata/sources/covers.py b/src/calibre/ebooks/metadata/sources/covers.py
index a7a12d652a..270e09738b 100644
--- a/src/calibre/ebooks/metadata/sources/covers.py
+++ b/src/calibre/ebooks/metadata/sources/covers.py
@@ -7,15 +7,15 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import time
-from threading import Thread, Event
 from io import StringIO
+from threading import Event, Thread
 
 from calibre.customize.ui import metadata_plugins
 from calibre.ebooks.metadata.sources.base import create_log
 from calibre.ebooks.metadata.sources.prefs import msprefs
-from calibre.utils.img import save_cover_data_to, remove_borders_from_image, image_to_data, image_from_data
+from calibre.utils.img import image_from_data, image_to_data, remove_borders_from_image, save_cover_data_to
 from calibre.utils.imghdr import identify
-from polyglot.queue import Queue, Empty
+from polyglot.queue import Empty, Queue
 
 
 class Worker(Thread):
diff --git a/src/calibre/ebooks/metadata/sources/edelweiss.py b/src/calibre/ebooks/metadata/sources/edelweiss.py
index 0d0501daf4..0326e22995 100644
--- a/src/calibre/ebooks/metadata/sources/edelweiss.py
+++ b/src/calibre/ebooks/metadata/sources/edelweiss.py
@@ -6,8 +6,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import time, re
+import re
+import time
 from threading import Thread
+
 try:
     from queue import Empty, Queue
 except ImportError:
@@ -106,6 +108,7 @@ class Worker(Thread):  # {{{
 
     def render_comments(self, desc):
         from lxml import etree
+
         from calibre.library.comments import sanitize_comments_html
         for c in desc.xpath('descendant::noscript'):
             c.getparent().remove(c)
@@ -126,8 +129,9 @@ class Worker(Thread):  # {{{
 
 
 def get_basic_data(browser, log, *skus):
-    from calibre.utils.date import parse_only_date
     from mechanize import Request
+
+    from calibre.utils.date import parse_only_date
     zeroes = ','.join('0' for sku in skus)
     data = {
             'skus': ','.join(skus),
@@ -377,8 +381,7 @@ class Edelweiss(Source):
 
 
 if __name__ == '__main__':
-    from calibre.ebooks.metadata.sources.test import (
-        test_identify_plugin, title_test, authors_test, comments_test, pubdate_test)
+    from calibre.ebooks.metadata.sources.test import authors_test, comments_test, pubdate_test, test_identify_plugin, title_test
     tests = [
         (  # A title and author search
          {'title': 'The Husband\'s Secret', 'authors':['Liane Moriarty']},
diff --git a/src/calibre/ebooks/metadata/sources/google.py b/src/calibre/ebooks/metadata/sources/google.py
index b9b1c244bc..5dee08e26b 100644
--- a/src/calibre/ebooks/metadata/sources/google.py
+++ b/src/calibre/ebooks/metadata/sources/google.py
@@ -2,20 +2,22 @@
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
 # License: GPLv3 Copyright: 2011, Kovid Goyal <kovid at kovidgoyal.net>
 from __future__ import absolute_import, division, print_function, unicode_literals
+
 import hashlib
 import os
 import re
-import regex
 import sys
 import tempfile
 import time
 
+import regex
+
 try:
     from queue import Empty, Queue
 except ImportError:
     from Queue import Empty, Queue
 
-from calibre import as_unicode, replace_entities, prepare_string_for_xml
+from calibre import as_unicode, prepare_string_for_xml, replace_entities
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.ebooks.metadata import authors_to_string, check_isbn
 from calibre.ebooks.metadata.book.base import Metadata
@@ -543,9 +545,7 @@ class GoogleBooks(Source):
 if __name__ == '__main__':  # tests {{{
     # To run these test use:
     # calibre-debug src/calibre/ebooks/metadata/sources/google.py
-    from calibre.ebooks.metadata.sources.test import (
-        authors_test, test_identify_plugin, title_test
-    )
+    from calibre.ebooks.metadata.sources.test import authors_test, test_identify_plugin, title_test
     tests = [
     ({
         'identifiers': {'google': 's7NIrgEACAAJ'},
diff --git a/src/calibre/ebooks/metadata/sources/google_images.py b/src/calibre/ebooks/metadata/sources/google_images.py
index 08631e082e..8a9521a272 100644
--- a/src/calibre/ebooks/metadata/sources/google_images.py
+++ b/src/calibre/ebooks/metadata/sources/google_images.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 from collections import OrderedDict
 
 from calibre import random_user_agent
-from calibre.ebooks.metadata.sources.base import Source, Option
+from calibre.ebooks.metadata.sources.base import Option, Source
 
 
 def parse_html(raw):
@@ -108,8 +108,8 @@ class GoogleImages(Source):
         # See https://github.com/benbusby/whoogle-search/pull/1054 for cookies
         br.set_simple_cookie('CONSENT', 'PENDING+987', '.google.com', path='/')
         template = b'\x08\x01\x128\x08\x14\x12+boq_identityfrontenduiserver_20231107.05_p0\x1a\x05en-US \x03\x1a\x06\x08\x80\xf1\xca\xaa\x06'
-        from datetime import date
         from base64 import standard_b64encode
+        from datetime import date
         template.replace(b'20231107', date.today().strftime('%Y%m%d').encode('ascii'))
         br.set_simple_cookie('SOCS', standard_b64encode(template).decode('ascii').rstrip('='), '.google.com', path='/')
         # br.set_debug_http(True)
@@ -136,6 +136,7 @@ def test():
     except ImportError:
         from Queue import Queue
     from threading import Event
+
     from calibre.utils.logging import default_log
     p = GoogleImages(None)
     p.log = default_log
diff --git a/src/calibre/ebooks/metadata/sources/identify.py b/src/calibre/ebooks/metadata/sources/identify.py
index d400b25dea..99f82daf11 100644
--- a/src/calibre/ebooks/metadata/sources/identify.py
+++ b/src/calibre/ebooks/metadata/sources/identify.py
@@ -6,8 +6,8 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import re
-import unicodedata
 import time
+import unicodedata
 from datetime import datetime
 from io import StringIO
 from operator import attrgetter
@@ -23,7 +23,7 @@ from calibre.utils.date import UNDEFINED_DATE, as_utc, utc_tz
 from calibre.utils.formatter import EvalFormatter
 from calibre.utils.html2text import html2text
 from calibre.utils.icu import lower, primary_sort_key
-from polyglot.builtins import iteritems, itervalues, as_unicode
+from polyglot.builtins import as_unicode, iteritems, itervalues
 from polyglot.queue import Empty, Queue
 from polyglot.urllib import quote, urlparse
 
@@ -640,9 +640,7 @@ def urls_from_identifiers(identifiers, sort_results=False):  # {{{
 
 def tests(start=0, limit=256):  # tests {{{
     # To run these test use: calibre-debug -c "from calibre.ebooks.metadata.sources.identify import tests; tests()"
-    from calibre.ebooks.metadata.sources.test import (
-        authors_test, test_identify, title_test
-    )
+    from calibre.ebooks.metadata.sources.test import authors_test, test_identify, title_test
     tests = [
             (
                 {'title':'Magykal Papers',
diff --git a/src/calibre/ebooks/metadata/sources/search_engines.py b/src/calibre/ebooks/metadata/sources/search_engines.py
index 765e66bbbd..32a3a22d87 100644
--- a/src/calibre/ebooks/metadata/sources/search_engines.py
+++ b/src/calibre/ebooks/metadata/sources/search_engines.py
@@ -3,25 +3,29 @@
 # License: GPLv3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
 
 from __future__ import absolute_import, division, print_function, unicode_literals
+
 import json
-import sys
 import os
 import re
+import sys
 import time
 from collections import namedtuple
 from contextlib import contextmanager
-from threading import Lock
 from functools import partial
+from threading import Lock
 
 try:
-    from urllib.parse import parse_qs, quote_plus, urlencode, quote, urlparse
+    from urllib.parse import parse_qs, quote, quote_plus, urlencode, urlparse
 except ImportError:
+    from urllib import quote, quote_plus, urlencode
+
     from urlparse import parse_qs, urlparse
-    from urllib import quote_plus, urlencode, quote
 
 from lxml import etree
 
-from calibre import browser as _browser, prints as safe_print, random_user_agent
+from calibre import browser as _browser
+from calibre import prints as safe_print
+from calibre import random_user_agent
 from calibre.constants import cache_dir
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.utils.lock import ExclusiveFile
@@ -333,8 +337,8 @@ def google_parse_results(root, raw, log=prints, ignore_uncached=True):
 
 def google_consent_cookies():
     # See https://github.com/benbusby/whoogle-search/pull/1054 for cookies
-    from datetime import date
     from base64 import standard_b64encode
+    from datetime import date
     base = {'domain': '.google.com', 'path': '/'}
     b = base.copy()
     b['name'], b['value'] = 'CONSENT', 'PENDING+987'
diff --git a/src/calibre/ebooks/metadata/sources/worker.py b/src/calibre/ebooks/metadata/sources/worker.py
index 98d3ddf686..66d5122ad8 100644
--- a/src/calibre/ebooks/metadata/sources/worker.py
+++ b/src/calibre/ebooks/metadata/sources/worker.py
@@ -3,8 +3,8 @@
 # License: GPLv3 Copyright: 2012, Kovid Goyal <kovid at kovidgoyal.net>
 import os
 from collections import Counter
-from io import BytesIO
 from functools import wraps
+from io import BytesIO
 from threading import Event, Thread
 
 from calibre.customize.ui import metadata_plugins
diff --git a/src/calibre/ebooks/metadata/tag_mapper.py b/src/calibre/ebooks/metadata/tag_mapper.py
index 5143c7fbcd..904dc0038f 100644
--- a/src/calibre/ebooks/metadata/tag_mapper.py
+++ b/src/calibre/ebooks/metadata/tag_mapper.py
@@ -4,7 +4,8 @@
 
 from collections import deque
 
-from calibre.utils.icu import lower as icu_lower, upper as icu_upper
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 from polyglot.builtins import as_unicode
 
 
diff --git a/src/calibre/ebooks/metadata/toc.py b/src/calibre/ebooks/metadata/toc.py
index 68d1ceb164..80956e3ac7 100644
--- a/src/calibre/ebooks/metadata/toc.py
+++ b/src/calibre/ebooks/metadata/toc.py
@@ -4,7 +4,10 @@
 __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, glob, re, functools
+import functools
+import glob
+import os
+import re
 from collections import Counter
 
 from lxml import etree
@@ -12,8 +15,8 @@ from lxml.builder import ElementMaker
 
 from calibre.constants import __appname__, __version__
 from calibre.ebooks.chardet import xml_to_unicode
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.utils.cleantext import clean_xml_chars
+from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.urllib import unquote, urlparse
 
 NCX_NS = "http://www.daisy.org/z3986/2005/ncx/"
@@ -25,8 +28,9 @@ C = ElementMaker(namespace=CALIBRE_NS, nsmap=NSMAP)
 
 def parse_html_toc(data):
     from html5_parser import parse
-    from calibre.utils.cleantext import clean_xml_chars
     from lxml import etree
+
+    from calibre.utils.cleantext import clean_xml_chars
     if isinstance(data, bytes):
         data = xml_to_unicode(data, strip_encoding_pats=True, resolve_entities=True)[0]
     root = parse(clean_xml_chars(data), maybe_xhtml=True, keep_doctype=False, sanitize_names=True)
diff --git a/src/calibre/ebooks/metadata/topaz.py b/src/calibre/ebooks/metadata/topaz.py
index df123fa59e..137f750dda 100644
--- a/src/calibre/ebooks/metadata/topaz.py
+++ b/src/calibre/ebooks/metadata/topaz.py
@@ -3,11 +3,13 @@ __copyright__ = '2010, Greg Riker <griker@hotmail.com>'
 __docformat__ = 'restructuredtext en'
 
 ''' Read/write metadata from Amazon's topaz format '''
-import io, sys, numbers
+import io
+import numbers
+import sys
 from struct import pack
 
-from calibre.ebooks.metadata import MetaInformation
 from calibre import force_unicode
+from calibre.ebooks.metadata import MetaInformation
 from polyglot.builtins import codepoint_to_chr, int_to_byte
 
 
diff --git a/src/calibre/ebooks/metadata/txt.py b/src/calibre/ebooks/metadata/txt.py
index 366fefdc84..496ee9c03f 100644
--- a/src/calibre/ebooks/metadata/txt.py
+++ b/src/calibre/ebooks/metadata/txt.py
@@ -5,7 +5,8 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 Read meta information from TXT files
 '''
 
-import re, os
+import os
+import re
 
 from calibre.ebooks.metadata import MetaInformation
 
diff --git a/src/calibre/ebooks/metadata/xisbn.py b/src/calibre/ebooks/metadata/xisbn.py
index d97c867549..571e318fa0 100644
--- a/src/calibre/ebooks/metadata/xisbn.py
+++ b/src/calibre/ebooks/metadata/xisbn.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import threading, re, json
+import json
+import re
+import threading
 
 from calibre import browser
 
@@ -101,7 +103,8 @@ class xISBN:
 xisbn = xISBN()
 
 if __name__ == '__main__':
-    import sys, pprint
+    import pprint
+    import sys
     isbn = sys.argv[-1]
     print(pprint.pprint(xisbn.get_data(isbn)))
     print()
diff --git a/src/calibre/ebooks/metadata/xmp.py b/src/calibre/ebooks/metadata/xmp.py
index b7c72992d3..1dfabe3194 100644
--- a/src/calibre/ebooks/metadata/xmp.py
+++ b/src/calibre/ebooks/metadata/xmp.py
@@ -4,20 +4,23 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import re, sys, copy, json
-from itertools import repeat
+import copy
+import json
+import re
+import sys
 from collections import defaultdict
+from itertools import repeat
 
 from lxml import etree
 from lxml.builder import ElementMaker
 
 from calibre import prints
-from calibre.ebooks.metadata import string_to_authors, check_isbn, check_doi
-from calibre.utils.xml_parse import safe_xml_fromstring
+from calibre.ebooks.metadata import check_doi, check_isbn, string_to_authors
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.opf2 import dump_dict
-from calibre.utils.date import parse_date, isoformat, now
+from calibre.utils.date import isoformat, now, parse_date
 from calibre.utils.localization import canonicalize_lang, lang_as_iso639_1
+from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.builtins import iteritems, string_or_bytes
 
 _xml_declaration = re.compile(r'<\?xml[^<>]+encoding\s*=\s*[\'"](.*?)[\'"][^<>]*>', re.IGNORECASE)
@@ -172,8 +175,8 @@ def read_series(root):
 
 
 def read_user_metadata(mi, root):
-    from calibre.utils.config import from_json
     from calibre.ebooks.metadata.book.json_codec import decode_is_multiple
+    from calibre.utils.config import from_json
     fields = set()
     for item in XPath('//calibre:custom_metadata')(root):
         for li in XPath('./rdf:Bag/rdf:li')(item):
@@ -442,8 +445,8 @@ def create_series(calibre, series, series_index):
 
 
 def create_user_metadata(calibre, all_user_metadata):
+    from calibre.ebooks.metadata.book.json_codec import encode_is_multiple, object_to_unicode
     from calibre.utils.config import to_json
-    from calibre.ebooks.metadata.book.json_codec import object_to_unicode, encode_is_multiple
 
     s = calibre.makeelement(expand('calibre:custom_metadata'))
     calibre.append(s)
diff --git a/src/calibre/ebooks/metadata/zip.py b/src/calibre/ebooks/metadata/zip.py
index e900c32616..ba91a1a352 100644
--- a/src/calibre/ebooks/metadata/zip.py
+++ b/src/calibre/ebooks/metadata/zip.py
@@ -3,14 +3,14 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 
-from calibre.utils.zipfile import ZipFile
-from calibre.ptempfile import TemporaryDirectory
 from calibre import CurrentDir
+from calibre.ptempfile import TemporaryDirectory
+from calibre.utils.zipfile import ZipFile
 
 
 def get_metadata(stream):
-    from calibre.ebooks.metadata.meta import get_metadata
     from calibre.ebooks.metadata.archive import is_comic
+    from calibre.ebooks.metadata.meta import get_metadata
     stream_type = None
     zf = ZipFile(stream, 'r')
     names = zf.namelist()
diff --git a/src/calibre/ebooks/mobi/debug/headers.py b/src/calibre/ebooks/mobi/debug/headers.py
index 59e62f68f0..15677599f6 100644
--- a/src/calibre/ebooks/mobi/debug/headers.py
+++ b/src/calibre/ebooks/mobi/debug/headers.py
@@ -5,13 +5,17 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import struct, datetime, os, numbers, binascii
+import binascii
+import datetime
+import numbers
+import os
+import struct
 
-from calibre.utils.date import utc_tz
-from calibre.ebooks.mobi.reader.headers import NULL_INDEX
-from calibre.ebooks.mobi.langcodes import main_language, sub_language
 from calibre.ebooks.mobi.debug import format_bytes
+from calibre.ebooks.mobi.langcodes import main_language, sub_language
+from calibre.ebooks.mobi.reader.headers import NULL_INDEX
 from calibre.ebooks.mobi.utils import get_trailing_data
+from calibre.utils.date import utc_tz
 from polyglot.builtins import iteritems
 
 # PalmDB {{{
diff --git a/src/calibre/ebooks/mobi/debug/index.py b/src/calibre/ebooks/mobi/debug/index.py
index 7ded8ab4d2..d9369ff5ab 100644
--- a/src/calibre/ebooks/mobi/debug/index.py
+++ b/src/calibre/ebooks/mobi/debug/index.py
@@ -9,10 +9,7 @@ import struct
 from collections import OrderedDict, namedtuple
 
 from calibre.ebooks.mobi.reader.headers import NULL_INDEX
-from calibre.ebooks.mobi.reader.index import (
-    CNCX, INDEX_HEADER_FIELDS, get_tag_section_start, parse_index_record,
-    parse_indx_header, parse_tagx_section
-)
+from calibre.ebooks.mobi.reader.index import CNCX, INDEX_HEADER_FIELDS, get_tag_section_start, parse_index_record, parse_indx_header, parse_tagx_section
 from calibre.ebooks.mobi.reader.ncx import default_entry, tag_fieldname_map
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/ebooks/mobi/debug/main.py b/src/calibre/ebooks/mobi/debug/main.py
index de7fc6f7d4..b2edacd7d6 100644
--- a/src/calibre/ebooks/mobi/debug/main.py
+++ b/src/calibre/ebooks/mobi/debug/main.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, shutil
+import os
+import shutil
+import sys
 
 from calibre.ebooks.mobi.debug.headers import MOBIFile
 from calibre.ebooks.mobi.debug.mobi6 import inspect_mobi as inspect_mobi6
diff --git a/src/calibre/ebooks/mobi/debug/mobi6.py b/src/calibre/ebooks/mobi/debug/mobi6.py
index 32193b9bd2..5cc26b8961 100644
--- a/src/calibre/ebooks/mobi/debug/mobi6.py
+++ b/src/calibre/ebooks/mobi/debug/mobi6.py
@@ -5,20 +5,20 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import struct, sys, os
+import os
+import struct
+import sys
 from collections import OrderedDict, defaultdict
 
 from lxml import html
 
-from calibre.ebooks.mobi.reader.headers import NULL_INDEX
-from calibre.ebooks.mobi.reader.index import (parse_index_record,
-        parse_tagx_section)
-from calibre.ebooks.mobi.utils import (decode_hex_number, decint,
-        decode_tbs, read_font_record)
-from calibre.utils.imghdr import what
 from calibre.ebooks.mobi.debug import format_bytes
 from calibre.ebooks.mobi.debug.headers import TextRecord
-from polyglot.builtins import iteritems, as_bytes, print_to_binary_file
+from calibre.ebooks.mobi.reader.headers import NULL_INDEX
+from calibre.ebooks.mobi.reader.index import parse_index_record, parse_tagx_section
+from calibre.ebooks.mobi.utils import decint, decode_hex_number, decode_tbs, read_font_record
+from calibre.utils.imghdr import what
+from polyglot.builtins import as_bytes, iteritems, print_to_binary_file
 
 
 class TagX:  # {{{
diff --git a/src/calibre/ebooks/mobi/debug/mobi8.py b/src/calibre/ebooks/mobi/debug/mobi8.py
index a9aa0f5fc8..b307caedb3 100644
--- a/src/calibre/ebooks/mobi/debug/mobi8.py
+++ b/src/calibre/ebooks/mobi/debug/mobi8.py
@@ -5,16 +5,18 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, struct, textwrap
+import os
+import struct
+import sys
+import textwrap
 
 from calibre import CurrentDir
+from calibre.ebooks.mobi.debug import format_bytes
 from calibre.ebooks.mobi.debug.containers import ContainerHeader
 from calibre.ebooks.mobi.debug.headers import TextRecord
-from calibre.ebooks.mobi.debug.index import (SKELIndex, SECTIndex, NCXIndex,
-        GuideIndex)
-from calibre.ebooks.mobi.utils import read_font_record, decode_tbs, RECORD_SIZE
-from calibre.ebooks.mobi.debug import format_bytes
+from calibre.ebooks.mobi.debug.index import GuideIndex, NCXIndex, SECTIndex, SKELIndex
 from calibre.ebooks.mobi.reader.headers import NULL_INDEX
+from calibre.ebooks.mobi.utils import RECORD_SIZE, decode_tbs, read_font_record
 from calibre.utils.imghdr import what
 from polyglot.builtins import iteritems, itervalues, print_to_binary_file
 
@@ -223,9 +225,15 @@ class MOBIFile:
                 payload))
 
     def read_tbs(self):
-        from calibre.ebooks.mobi.writer8.tbs import (Entry, DOC,
-                collect_indexing_data, encode_strands_as_sequences,
-                sequences_to_bytes, calculate_all_tbs, NegativeStrandIndex)
+        from calibre.ebooks.mobi.writer8.tbs import (
+            DOC,
+            Entry,
+            NegativeStrandIndex,
+            calculate_all_tbs,
+            collect_indexing_data,
+            encode_strands_as_sequences,
+            sequences_to_bytes,
+        )
         entry_map = []
         for index in self.ncx_index:
             vals = list(index)[:-1] + [None, None, None, None]
diff --git a/src/calibre/ebooks/mobi/langcodes.py b/src/calibre/ebooks/mobi/langcodes.py
index 7f027de127..26b22ce847 100644
--- a/src/calibre/ebooks/mobi/langcodes.py
+++ b/src/calibre/ebooks/mobi/langcodes.py
@@ -6,6 +6,7 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
 from struct import pack
+
 from calibre.utils.localization import lang_as_iso639_1
 
 lang_codes = {
diff --git a/src/calibre/ebooks/mobi/mobiml.py b/src/calibre/ebooks/mobi/mobiml.py
index f9a3b6c195..3d6aa19148 100644
--- a/src/calibre/ebooks/mobi/mobiml.py
+++ b/src/calibre/ebooks/mobi/mobiml.py
@@ -9,12 +9,11 @@ import copy
 import numbers
 import re
 from contextlib import suppress
+
 from lxml import etree
 
 from calibre.ebooks.mobi.utils import convert_color_for_font_tag
-from calibre.ebooks.oeb.base import (
-    XHTML, XHTML_NS, barename, namespace, urlnormalize
-)
+from calibre.ebooks.oeb.base import XHTML, XHTML_NS, barename, namespace, urlnormalize
 from calibre.ebooks.oeb.stylizer import Stylizer
 from calibre.ebooks.oeb.transforms.flatcss import KeyMapper
 from calibre.utils.imghdr import identify
diff --git a/src/calibre/ebooks/mobi/reader/containers.py b/src/calibre/ebooks/mobi/reader/containers.py
index fcdd1120b5..5d367cd823 100644
--- a/src/calibre/ebooks/mobi/reader/containers.py
+++ b/src/calibre/ebooks/mobi/reader/containers.py
@@ -4,7 +4,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from struct import unpack_from, error
+from struct import error, unpack_from
 
 from calibre.utils.imghdr import what
 
diff --git a/src/calibre/ebooks/mobi/reader/headers.py b/src/calibre/ebooks/mobi/reader/headers.py
index 1f2419fbcb..9f0021cc43 100644
--- a/src/calibre/ebooks/mobi/reader/headers.py
+++ b/src/calibre/ebooks/mobi/reader/headers.py
@@ -5,16 +5,18 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import struct, re, os
+import os
+import re
+import struct
 
 from calibre import replace_entities
-from calibre.utils.date import parse_date
-from calibre.ebooks.mobi import MobiError
 from calibre.ebooks.metadata import MetaInformation, check_isbn
-from calibre.ebooks.mobi.langcodes import main_language, sub_language, mobi2iana
+from calibre.ebooks.mobi import MobiError
+from calibre.ebooks.mobi.langcodes import main_language, mobi2iana, sub_language
 from calibre.utils.cleantext import clean_ascii_chars, clean_xml_chars
-from calibre.utils.localization import canonicalize_lang
 from calibre.utils.config_base import tweaks
+from calibre.utils.date import parse_date
+from calibre.utils.localization import canonicalize_lang
 
 NULL_INDEX = 0xffffffff
 
diff --git a/src/calibre/ebooks/mobi/reader/index.py b/src/calibre/ebooks/mobi/reader/index.py
index 27f2b06eb1..aeb2f5d1d7 100644
--- a/src/calibre/ebooks/mobi/reader/index.py
+++ b/src/calibre/ebooks/mobi/reader/index.py
@@ -8,8 +8,7 @@ __docformat__ = 'restructuredtext en'
 import struct
 from collections import OrderedDict, namedtuple
 
-from calibre.ebooks.mobi.utils import (decint, count_set_bits,
-        decode_string)
+from calibre.ebooks.mobi.utils import count_set_bits, decint, decode_string
 from polyglot.builtins import iteritems
 
 TagX = namedtuple('TagX', 'tag num_of_values bitmask eof')
diff --git a/src/calibre/ebooks/mobi/reader/markup.py b/src/calibre/ebooks/mobi/reader/markup.py
index 34c54d2ea4..3578d63dcb 100644
--- a/src/calibre/ebooks/mobi/reader/markup.py
+++ b/src/calibre/ebooks/mobi/reader/markup.py
@@ -5,7 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, os
+import os
+import re
 
 from calibre.ebooks.chardet import strip_encoding_declarations
 
diff --git a/src/calibre/ebooks/mobi/reader/mobi6.py b/src/calibre/ebooks/mobi/reader/mobi6.py
index 75e43a1926..12fc7cd6bf 100644
--- a/src/calibre/ebooks/mobi/reader/mobi6.py
+++ b/src/calibre/ebooks/mobi/reader/mobi6.py
@@ -11,6 +11,7 @@ import re
 import shutil
 import struct
 import textwrap
+
 from lxml import etree, html
 
 from calibre import entity_to_unicode, guess_type, xml_entity_to_unicode
diff --git a/src/calibre/ebooks/mobi/reader/mobi8.py b/src/calibre/ebooks/mobi/reader/mobi8.py
index c1aa6acb0b..558dfb7da0 100644
--- a/src/calibre/ebooks/mobi/reader/mobi8.py
+++ b/src/calibre/ebooks/mobi/reader/mobi8.py
@@ -5,23 +5,25 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import struct, re, os
+import os
+import re
+import struct
 from collections import namedtuple
 from itertools import repeat
 from uuid import uuid4
 
 from lxml import etree
 
-from calibre.ebooks.mobi.reader.headers import NULL_INDEX
-from calibre.ebooks.mobi.reader.index import read_index
-from calibre.ebooks.mobi.reader.ncx import read_ncx, build_toc
-from calibre.ebooks.mobi.reader.markup import expand_mobi8_markup
-from calibre.ebooks.mobi.reader.containers import Container, find_imgtype
 from calibre.ebooks.metadata.opf2 import Guide, OPFCreator
 from calibre.ebooks.metadata.toc import TOC
+from calibre.ebooks.mobi.reader.containers import Container, find_imgtype
+from calibre.ebooks.mobi.reader.headers import NULL_INDEX
+from calibre.ebooks.mobi.reader.index import read_index
+from calibre.ebooks.mobi.reader.markup import expand_mobi8_markup
+from calibre.ebooks.mobi.reader.ncx import build_toc, read_ncx
 from calibre.ebooks.mobi.utils import read_font_record
+from calibre.ebooks.oeb.base import XHTML, XPath, xml2text
 from calibre.ebooks.oeb.parse_utils import parse_html
-from calibre.ebooks.oeb.base import XPath, XHTML, xml2text
 from polyglot.builtins import as_unicode
 from polyglot.urllib import urldefrag
 
diff --git a/src/calibre/ebooks/mobi/tweak.py b/src/calibre/ebooks/mobi/tweak.py
index b51bd4d08f..c38c5ac58a 100644
--- a/src/calibre/ebooks/mobi/tweak.py
+++ b/src/calibre/ebooks/mobi/tweak.py
@@ -5,19 +5,19 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, glob
+import glob
+import os
 
 from calibre import CurrentDir
-from calibre.ebooks.mobi import MobiError
-from calibre.ebooks.mobi.reader.mobi6 import MobiReader
-from calibre.ebooks.mobi.reader.headers import MetadataHeader
-from calibre.utils.logging import default_log
+from calibre.customize.ui import plugin_for_input_format, plugin_for_output_format
 from calibre.ebooks import DRMError
-from calibre.ebooks.mobi.reader.mobi8 import Mobi8Reader
 from calibre.ebooks.conversion.plumber import Plumber, create_oebbook
-from calibre.customize.ui import (plugin_for_input_format,
-        plugin_for_output_format)
+from calibre.ebooks.mobi import MobiError
+from calibre.ebooks.mobi.reader.headers import MetadataHeader
+from calibre.ebooks.mobi.reader.mobi6 import MobiReader
+from calibre.ebooks.mobi.reader.mobi8 import Mobi8Reader
 from calibre.utils.ipc.simple_worker import fork_job
+from calibre.utils.logging import default_log
 
 
 class BadFormat(ValueError):
diff --git a/src/calibre/ebooks/mobi/utils.py b/src/calibre/ebooks/mobi/utils.py
index 069a226b2e..59bcc513d1 100644
--- a/src/calibre/ebooks/mobi/utils.py
+++ b/src/calibre/ebooks/mobi/utils.py
@@ -5,16 +5,20 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import struct, string, zlib, os
+import os
+import string
+import struct
+import zlib
 from collections import OrderedDict
 from io import BytesIO
 
-from calibre.utils.img import save_cover_data_to, scale_image, image_to_data, image_from_data, resize_image, png_data_to_gif_data
-from calibre.utils.imghdr import what
-from calibre.ebooks import normalize
-from polyglot.builtins import as_bytes
 from tinycss.color3 import parse_color_string
 
+from calibre.ebooks import normalize
+from calibre.utils.img import image_from_data, image_to_data, png_data_to_gif_data, resize_image, save_cover_data_to, scale_image
+from calibre.utils.imghdr import what
+from polyglot.builtins import as_bytes
+
 IMAGE_MAX_SIZE = 10 * 1024 * 1024
 RECORD_SIZE = 0x1000  # 4096 (Text record size (uncompressed))
 
diff --git a/src/calibre/ebooks/mobi/writer2/indexer.py b/src/calibre/ebooks/mobi/writer2/indexer.py
index 80f337abc1..357b357d52 100644
--- a/src/calibre/ebooks/mobi/writer2/indexer.py
+++ b/src/calibre/ebooks/mobi/writer2/indexer.py
@@ -5,13 +5,13 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import numbers
-from struct import pack
 import io
+import numbers
 from collections import OrderedDict, defaultdict
+from struct import pack
 
-from calibre.ebooks.mobi.utils import (encint, encode_number_as_hex,
-        encode_tbs, align_block, RECORD_SIZE, CNCX as CNCX_)
+from calibre.ebooks.mobi.utils import CNCX as CNCX_
+from calibre.ebooks.mobi.utils import RECORD_SIZE, align_block, encint, encode_number_as_hex, encode_tbs
 from polyglot.builtins import iteritems, itervalues
 
 
diff --git a/src/calibre/ebooks/mobi/writer2/main.py b/src/calibre/ebooks/mobi/writer2/main.py
index 0f09b4e656..022008ed0e 100644
--- a/src/calibre/ebooks/mobi/writer2/main.py
+++ b/src/calibre/ebooks/mobi/writer2/main.py
@@ -5,18 +5,19 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import io, random, time
+import io
+import random
+import time
 from struct import pack
 
 from calibre.ebooks import normalize
-from calibre.ebooks.mobi.writer2.serializer import Serializer
 from calibre.ebooks.compression.palmdoc import compress_doc
 from calibre.ebooks.mobi.langcodes import iana2mobi
-from calibre.utils.filenames import ascii_filename
-from calibre.ebooks.mobi.writer2 import (PALMDOC, UNCOMPRESSED)
-from calibre.ebooks.mobi.utils import (encint, encode_trailing_data,
-        align_block, detect_periodical, RECORD_SIZE, create_text_record)
+from calibre.ebooks.mobi.utils import RECORD_SIZE, align_block, create_text_record, detect_periodical, encint, encode_trailing_data
+from calibre.ebooks.mobi.writer2 import PALMDOC, UNCOMPRESSED
 from calibre.ebooks.mobi.writer2.indexer import Indexer
+from calibre.ebooks.mobi.writer2.serializer import Serializer
+from calibre.utils.filenames import ascii_filename
 from polyglot.builtins import iteritems
 
 # Disabled as I dont care about uncrossable breaks
@@ -373,9 +374,8 @@ class MobiWriter:
     # }}}
 
     def generate_joint_record0(self):  # {{{
-        from calibre.ebooks.mobi.writer8.mobi import (MOBIHeader,
-                HEADER_FIELDS)
         from calibre.ebooks.mobi.writer8.exth import build_exth
+        from calibre.ebooks.mobi.writer8.mobi import HEADER_FIELDS, MOBIHeader
 
         # Insert resource records
         first_image_record = None
diff --git a/src/calibre/ebooks/mobi/writer2/resources.py b/src/calibre/ebooks/mobi/writer2/resources.py
index f75ba43aa4..592c1e6077 100644
--- a/src/calibre/ebooks/mobi/writer2/resources.py
+++ b/src/calibre/ebooks/mobi/writer2/resources.py
@@ -6,13 +6,13 @@ __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import os
-from PIL import Image, ImageOps
 from io import BytesIO
 
-from calibre.ebooks.mobi import MAX_THUMB_DIMEN, MAX_THUMB_SIZE
-from calibre.ebooks.mobi.utils import (rescale_image, mobify_image,
-        write_font_record)
+from PIL import Image, ImageOps
+
 from calibre.ebooks import generate_masthead
+from calibre.ebooks.mobi import MAX_THUMB_DIMEN, MAX_THUMB_SIZE
+from calibre.ebooks.mobi.utils import mobify_image, rescale_image, write_font_record
 from calibre.ebooks.oeb.base import OEB_RASTER_IMAGES
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.utils.imghdr import what
diff --git a/src/calibre/ebooks/mobi/writer2/serializer.py b/src/calibre/ebooks/mobi/writer2/serializer.py
index 5d6d3d33a1..fd25a58f39 100644
--- a/src/calibre/ebooks/mobi/writer2/serializer.py
+++ b/src/calibre/ebooks/mobi/writer2/serializer.py
@@ -13,9 +13,7 @@ from io import BytesIO
 
 from calibre.ebooks.mobi.mobiml import MBP_NS
 from calibre.ebooks.mobi.utils import is_guide_ref_start
-from calibre.ebooks.oeb.base import (
-    OEB_DOCS, XHTML, XHTML_NS, XML_NS, namespace, prefixname, urlnormalize
-)
+from calibre.ebooks.oeb.base import OEB_DOCS, XHTML, XHTML_NS, XML_NS, namespace, prefixname, urlnormalize
 from polyglot.builtins import string_or_bytes
 from polyglot.urllib import urldefrag
 
diff --git a/src/calibre/ebooks/mobi/writer8/exth.py b/src/calibre/ebooks/mobi/writer8/exth.py
index a6af8d21fa..ff69a45eef 100644
--- a/src/calibre/ebooks/mobi/writer8/exth.py
+++ b/src/calibre/ebooks/mobi/writer8/exth.py
@@ -6,13 +6,13 @@ __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import re
-from struct import pack
 from io import BytesIO
+from struct import pack
 
-from calibre.constants import iswindows, ismacos
-from calibre.ebooks.mobi.utils import (utf8_text, to_base)
-from calibre.utils.localization import lang_as_iso639_1
+from calibre.constants import ismacos, iswindows
 from calibre.ebooks.metadata import authors_to_sort_string
+from calibre.ebooks.mobi.utils import to_base, utf8_text
+from calibre.utils.localization import lang_as_iso639_1
 from polyglot.builtins import iteritems
 
 EXTH_CODES = {
diff --git a/src/calibre/ebooks/mobi/writer8/header.py b/src/calibre/ebooks/mobi/writer8/header.py
index cc539a60f6..839445128e 100644
--- a/src/calibre/ebooks/mobi/writer8/header.py
+++ b/src/calibre/ebooks/mobi/writer8/header.py
@@ -5,13 +5,14 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import random, numbers
-from io import BytesIO
+import numbers
+import random
 from collections import OrderedDict
+from io import BytesIO
 from struct import pack
 
 from calibre.ebooks.mobi.utils import align_block
-from polyglot.builtins import iteritems, as_bytes
+from polyglot.builtins import as_bytes, iteritems
 
 NULL = 0xffffffff
 def zeroes(x):
diff --git a/src/calibre/ebooks/mobi/writer8/index.py b/src/calibre/ebooks/mobi/writer8/index.py
index ef20c8966d..51b73d00e9 100644
--- a/src/calibre/ebooks/mobi/writer8/index.py
+++ b/src/calibre/ebooks/mobi/writer8/index.py
@@ -5,10 +5,10 @@ __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from collections import namedtuple
-from struct import pack
 from io import BytesIO
+from struct import pack
 
-from calibre.ebooks.mobi.utils import CNCX, encint, align_block
+from calibre.ebooks.mobi.utils import CNCX, align_block, encint
 from calibre.ebooks.mobi.writer8.header import Header
 
 TagMeta_ = namedtuple('TagMeta',
@@ -374,7 +374,8 @@ class NonLinearNCXIndex(NCXIndex):
 if __name__ == '__main__':
     # Generate a document with a large number of index entries using both
     # calibre and kindlegen and compare the output
-    import os, subprocess
+    import os
+    import subprocess
     os.chdir('/t')
     paras = ['<p>%d</p>' % i for i in range(4000)]
     raw = '<html><body>' + '\n\n'.join(paras) + '</body></html>'
diff --git a/src/calibre/ebooks/mobi/writer8/main.py b/src/calibre/ebooks/mobi/writer8/main.py
index fe056e129a..08f4c560e7 100644
--- a/src/calibre/ebooks/mobi/writer8/main.py
+++ b/src/calibre/ebooks/mobi/writer8/main.py
@@ -5,9 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import copy, logging
-from functools import partial
+import copy
+import logging
 from collections import defaultdict, namedtuple
+from functools import partial
 from io import BytesIO
 from struct import pack
 
@@ -15,20 +16,17 @@ import css_parser
 from css_parser.css import CSSRule
 from lxml import etree
 
-from calibre import isbytestring, force_unicode
-from calibre.ebooks.mobi.utils import (create_text_record, to_base,
-        is_guide_ref_start)
+from calibre import force_unicode, isbytestring
 from calibre.ebooks.compression.palmdoc import compress_doc
-from calibre.ebooks.oeb.base import (OEB_DOCS, OEB_STYLES, SVG_MIME, XPath,
-        extract, XHTML, urlnormalize)
-from calibre.ebooks.oeb.normalize_css import condense_sheet
-from calibre.ebooks.oeb.parse_utils import barename
-from calibre.ebooks.mobi.writer8.skeleton import Chunker, aid_able_tags, to_href
-from calibre.ebooks.mobi.writer8.index import (NCXIndex, SkelIndex,
-        ChunkIndex, GuideIndex, NonLinearNCXIndex)
+from calibre.ebooks.mobi.utils import create_text_record, is_guide_ref_start, to_base
+from calibre.ebooks.mobi.writer8.index import ChunkIndex, GuideIndex, NCXIndex, NonLinearNCXIndex, SkelIndex
 from calibre.ebooks.mobi.writer8.mobi import KF8Book
+from calibre.ebooks.mobi.writer8.skeleton import Chunker, aid_able_tags, to_href
 from calibre.ebooks.mobi.writer8.tbs import apply_trailing_byte_sequences
 from calibre.ebooks.mobi.writer8.toc import TOCAdder
+from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, SVG_MIME, XHTML, XPath, extract, urlnormalize
+from calibre.ebooks.oeb.normalize_css import condense_sheet
+from calibre.ebooks.oeb.parse_utils import barename
 from polyglot.builtins import iteritems
 
 XML_DOCS = OEB_DOCS | {SVG_MIME}
diff --git a/src/calibre/ebooks/mobi/writer8/mobi.py b/src/calibre/ebooks/mobi/writer8/mobi.py
index 58130e4ce3..8aed9c6c06 100644
--- a/src/calibre/ebooks/mobi/writer8/mobi.py
+++ b/src/calibre/ebooks/mobi/writer8/mobi.py
@@ -5,14 +5,15 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import time, random
+import random
+import time
 from struct import pack
 
-from calibre.ebooks.mobi.utils import RECORD_SIZE, utf8_text
-from calibre.ebooks.mobi.writer8.header import Header
-from calibre.ebooks.mobi.writer2 import (PALMDOC, UNCOMPRESSED)
 from calibre.ebooks.mobi.langcodes import iana2mobi
+from calibre.ebooks.mobi.utils import RECORD_SIZE, utf8_text
+from calibre.ebooks.mobi.writer2 import PALMDOC, UNCOMPRESSED
 from calibre.ebooks.mobi.writer8.exth import build_exth
+from calibre.ebooks.mobi.writer8.header import Header
 from calibre.utils.filenames import ascii_filename
 
 NULL_INDEX = 0xffffffff
diff --git a/src/calibre/ebooks/mobi/writer8/skeleton.py b/src/calibre/ebooks/mobi/writer8/skeleton.py
index a42ce358fc..fceb018c9d 100644
--- a/src/calibre/ebooks/mobi/writer8/skeleton.py
+++ b/src/calibre/ebooks/mobi/writer8/skeleton.py
@@ -13,9 +13,9 @@ from xml.sax.saxutils import escape
 from lxml import etree
 
 from calibre import my_unichr
+from calibre.ebooks.mobi.utils import PolyglotDict, to_base
 from calibre.ebooks.oeb.base import XHTML_NS, extract
-from calibre.ebooks.mobi.utils import to_base, PolyglotDict
-from polyglot.builtins import iteritems, as_bytes
+from polyglot.builtins import as_bytes, iteritems
 
 CHUNK_SIZE = 8192
 
@@ -413,7 +413,9 @@ class Chunker:
                 text)
 
     def dump(self, orig_dumps):
-        import tempfile, shutil, os
+        import os
+        import shutil
+        import tempfile
         tdir = os.path.join(tempfile.gettempdir(), 'skeleton')
         self.log('Skeletons dumped to:', tdir)
         if os.path.exists(tdir):
diff --git a/src/calibre/ebooks/mobi/writer8/tbs.py b/src/calibre/ebooks/mobi/writer8/tbs.py
index 68f1c3c604..ce02158fd8 100644
--- a/src/calibre/ebooks/mobi/writer8/tbs.py
+++ b/src/calibre/ebooks/mobi/writer8/tbs.py
@@ -16,11 +16,10 @@ For the exact algorithm, see separate_strands(). The strands are then encoded
 into 'sequences', see encode_strands_as_sequences() and finally the sequences
 are turned into bytes.
 '''
-from collections import namedtuple, OrderedDict
+from collections import OrderedDict, namedtuple
 from operator import attrgetter
 
-from calibre.ebooks.mobi.utils import (encode_trailing_data,
-        encode_tbs)
+from calibre.ebooks.mobi.utils import encode_tbs, encode_trailing_data
 from polyglot.builtins import iteritems, itervalues
 
 Entry = namedtuple('IndexEntry', 'index start length depth parent '
diff --git a/src/calibre/ebooks/mobi/writer8/toc.py b/src/calibre/ebooks/mobi/writer8/toc.py
index 3ec2e57cf0..2d3e36f80c 100644
--- a/src/calibre/ebooks/mobi/writer8/toc.py
+++ b/src/calibre/ebooks/mobi/writer8/toc.py
@@ -5,9 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.ebooks.oeb.base import (
-    XHTML, XHTML_MIME, XHTML_NS, XPath, css_text, urlnormalize,
-)
+from calibre.ebooks.oeb.base import XHTML, XHTML_MIME, XHTML_NS, XPath, css_text, urlnormalize
 from calibre.utils.localization import __
 from calibre.utils.xml_parse import safe_xml_fromstring
 
diff --git a/src/calibre/ebooks/odt/input.py b/src/calibre/ebooks/odt/input.py
index b90045e8ca..73e0c21e8d 100644
--- a/src/calibre/ebooks/odt/input.py
+++ b/src/calibre/ebooks/odt/input.py
@@ -5,21 +5,22 @@ __docformat__ = 'restructuredtext en'
 '''
 Convert an ODT file into a Open Ebook
 '''
-import os, logging
+import logging
+import os
 
-from lxml import etree
 from css_parser import CSSParser
 from css_parser.css import CSSRule
-
+from lxml import etree
+from odf.draw import Frame as odFrame
+from odf.draw import Image as odImage
+from odf.namespaces import TEXTNS as odTEXTNS
 from odf.odf2xhtml import ODF2XHTML
 from odf.opendocument import load as odLoad
-from odf.draw import Frame as odFrame, Image as odImage
-from odf.namespaces import TEXTNS as odTEXTNS
 
 from calibre import CurrentDir, walk
 from calibre.ebooks.oeb.base import _css_logger
 from calibre.utils.xml_parse import safe_xml_fromstring
-from polyglot.builtins import string_or_bytes, as_bytes
+from polyglot.builtins import as_bytes, string_or_bytes
 
 
 class Extract(ODF2XHTML):
@@ -87,7 +88,7 @@ class Extract(ODF2XHTML):
                     return rule
 
     def epubify_markup(self, root, log):
-        from calibre.ebooks.oeb.base import XPath, XHTML
+        from calibre.ebooks.oeb.base import XHTML, XPath
         # Fix empty title tags
         for t in XPath('//h:title')(root):
             if not t.text:
@@ -264,9 +265,9 @@ class Extract(ODF2XHTML):
         self._walknode(self.document.topnode)
 
     def __call__(self, stream, odir, log):
-        from calibre.utils.zipfile import ZipFile
         from calibre.ebooks.metadata.odt import get_metadata
         from calibre.ebooks.metadata.opf2 import OPFCreator
+        from calibre.utils.zipfile import ZipFile
 
         if not os.path.exists(odir):
             os.makedirs(odir)
diff --git a/src/calibre/ebooks/oeb/base.py b/src/calibre/ebooks/oeb/base.py
index 133dc7ebe1..c2b404ca49 100644
--- a/src/calibre/ebooks/oeb/base.py
+++ b/src/calibre/ebooks/oeb/base.py
@@ -13,27 +13,26 @@ import re
 import sys
 from collections import defaultdict
 from itertools import count
-from lxml import etree, html
 from operator import attrgetter
 from typing import Optional
 
+from lxml import etree, html
+
 from calibre import as_unicode, force_unicode, get_types_map, isbytestring
 from calibre.constants import __version__, filesystem_encoding
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.ebooks.conversion.preprocess import CSSPreProcessor
-from calibre.ebooks.oeb.parse_utils import (
-    XHTML, XHTML_NS, NotHTML, barename, namespace, parse_html,
-)
+from calibre.ebooks.oeb.parse_utils import XHTML, XHTML_NS, NotHTML, barename, namespace, parse_html
 from calibre.translations.dynamic import translate
 from calibre.utils.cleantext import clean_xml_chars
-from calibre.utils.icu import numeric_sort_key, title_case as icu_title
+from calibre.utils.icu import numeric_sort_key
+from calibre.utils.icu import title_case as icu_title
 from calibre.utils.localization import __
 from calibre.utils.short_uuid import uuid4
 from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.builtins import codepoint_to_chr, iteritems, itervalues, string_or_bytes
-from polyglot.urllib import (
-    unquote as urlunquote, urldefrag, urljoin, urlparse, urlunparse,
-)
+from polyglot.urllib import unquote as urlunquote
+from polyglot.urllib import urldefrag, urljoin, urlparse, urlunparse
 
 XML_NS       = 'http://www.w3.org/XML/1998/namespace'
 OEB_DOC_NS   = 'http://openebook.org/namespaces/oeb-document/1.0/'
diff --git a/src/calibre/ebooks/oeb/display/webview.py b/src/calibre/ebooks/oeb/display/webview.py
index ae9ada9517..ad6a64f069 100644
--- a/src/calibre/ebooks/oeb/display/webview.py
+++ b/src/calibre/ebooks/oeb/display/webview.py
@@ -49,7 +49,7 @@ def load_as_html(html):
 def load_html(path, view, codec='utf-8', mime_type=None,
               pre_load_callback=lambda x:None, path_is_html=False,
               force_as_html=False, loading_url=None):
-    from qt.core import QUrl, QByteArray
+    from qt.core import QByteArray, QUrl
     if mime_type is None:
         mime_type = guess_type(path)[0]
         if not mime_type:
diff --git a/src/calibre/ebooks/oeb/iterator/__init__.py b/src/calibre/ebooks/oeb/iterator/__init__.py
index f821fc427e..fa464f7edc 100644
--- a/src/calibre/ebooks/oeb/iterator/__init__.py
+++ b/src/calibre/ebooks/oeb/iterator/__init__.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, re
+import os
+import re
+import sys
 
 from calibre.customize.ui import available_input_formats
 
@@ -29,9 +31,9 @@ def EbookIterator(*args, **kwargs):
 
 
 def get_preprocess_html(path_to_ebook, output=None):
-    from calibre.ebooks.conversion.plumber import set_regex_wizard_callback, Plumber
-    from calibre.utils.logging import DevNull
+    from calibre.ebooks.conversion.plumber import Plumber, set_regex_wizard_callback
     from calibre.ptempfile import TemporaryDirectory
+    from calibre.utils.logging import DevNull
     raw = {}
     set_regex_wizard_callback(raw.__setitem__)
     with TemporaryDirectory('_regex_wiz') as tdir:
diff --git a/src/calibre/ebooks/oeb/iterator/book.py b/src/calibre/ebooks/oeb/iterator/book.py
index 3f3ae5edfc..f58a870542 100644
--- a/src/calibre/ebooks/oeb/iterator/book.py
+++ b/src/calibre/ebooks/oeb/iterator/book.py
@@ -10,19 +10,21 @@ __docformat__ = 'restructuredtext en'
 Iterate over the HTML files in an ebook. Useful for writing viewers.
 '''
 
-import re, os, math
+import math
+import os
+import re
 from functools import partial
 
+from calibre import guess_type, prepare_string_for_xml
 from calibre.ebooks.metadata.opf2 import OPF
+from calibre.ebooks.oeb.base import urlparse, urlunquote
+from calibre.ebooks.oeb.iterator.bookmarks import BookmarksMixin
+from calibre.ebooks.oeb.iterator.spine import SpineItem, create_indexing_data
+from calibre.ebooks.oeb.transforms.cover import CoverManager
 from calibre.ptempfile import PersistentTemporaryDirectory, remove_dir
 from calibre.utils.config import DynamicConfig
 from calibre.utils.logging import default_log
 from calibre.utils.tdir_in_cache import tdir_in_cache
-from calibre import guess_type, prepare_string_for_xml
-from calibre.ebooks.oeb.transforms.cover import CoverManager
-from calibre.ebooks.oeb.iterator.spine import (SpineItem, create_indexing_data)
-from calibre.ebooks.oeb.iterator.bookmarks import BookmarksMixin
-from calibre.ebooks.oeb.base import urlparse, urlunquote
 
 TITLEPAGE = CoverManager.SVG_TEMPLATE.replace(
         '__ar__', 'none').replace('__viewbox__', '0 0 600 800'
@@ -37,8 +39,8 @@ class FakeOpts:
 
 
 def write_oebbook(oeb, path):
-    from calibre.ebooks.oeb.writer import OEBWriter
     from calibre import walk
+    from calibre.ebooks.oeb.writer import OEBWriter
     w = OEBWriter()
     w(oeb, path)
     for f in walk(path):
diff --git a/src/calibre/ebooks/oeb/iterator/bookmarks.py b/src/calibre/ebooks/oeb/iterator/bookmarks.py
index c28d2e5f21..c410da57c3 100644
--- a/src/calibre/ebooks/oeb/iterator/bookmarks.py
+++ b/src/calibre/ebooks/oeb/iterator/bookmarks.py
@@ -5,7 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, numbers
+import numbers
+import os
 from io import BytesIO
 
 from calibre.utils.zipfile import safe_replace
diff --git a/src/calibre/ebooks/oeb/iterator/spine.py b/src/calibre/ebooks/oeb/iterator/spine.py
index 342b63b901..8eca669c07 100644
--- a/src/calibre/ebooks/oeb/iterator/spine.py
+++ b/src/calibre/ebooks/oeb/iterator/spine.py
@@ -5,10 +5,11 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, os
+import os
+import re
+from collections import namedtuple
 from functools import partial
 from operator import attrgetter
-from collections import namedtuple
 
 from calibre import guess_type, replace_entities
 from calibre.ebooks.chardet import xml_to_unicode
diff --git a/src/calibre/ebooks/oeb/normalize_css.py b/src/calibre/ebooks/oeb/normalize_css.py
index 941d000b6c..aed56f5691 100644
--- a/src/calibre/ebooks/oeb/normalize_css.py
+++ b/src/calibre/ebooks/oeb/normalize_css.py
@@ -7,9 +7,11 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import numbers
 from functools import wraps
 
+from css_parser import CSSParser
+from css_parser import profile as cssprofiles
 from css_parser.css import PropertyValue
-from css_parser import profile as cssprofiles, CSSParser
 from tinycss.fonts3 import parse_font, serialize_font_family
+
 from calibre.ebooks.oeb.base import css_text
 from polyglot.builtins import iteritems, string_or_bytes
 
@@ -266,9 +268,10 @@ def condense_sheet(sheet):
 
 def test_normalization(return_tests=False):  # {{{
     import unittest
-    from css_parser import parseStyle
     from itertools import product
 
+    from css_parser import parseStyle
+
     class TestNormalization(unittest.TestCase):
         longMessage = True
         maxDiff = None
diff --git a/src/calibre/ebooks/oeb/parse_utils.py b/src/calibre/ebooks/oeb/parse_utils.py
index 2d32420441..9b18af37e8 100644
--- a/src/calibre/ebooks/oeb/parse_utils.py
+++ b/src/calibre/ebooks/oeb/parse_utils.py
@@ -9,10 +9,10 @@ import re
 
 from lxml import etree, html
 
-from calibre import xml_replace_entities, force_unicode
-from calibre.utils.xml_parse import safe_xml_fromstring
+from calibre import force_unicode, xml_replace_entities
 from calibre.constants import filesystem_encoding
-from calibre.ebooks.chardet import xml_to_unicode, strip_encoding_declarations
+from calibre.ebooks.chardet import strip_encoding_declarations, xml_to_unicode
+from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.builtins import iteritems, itervalues, string_or_bytes
 
 RECOVER_PARSER = etree.XMLParser(recover=True, no_network=True, resolve_entities=False)
@@ -94,6 +94,7 @@ def node_depth(node):
 
 def html5_parse(data, max_nesting_depth=100):
     from html5_parser import parse
+
     from calibre.utils.cleantext import clean_xml_chars
     data = parse(clean_xml_chars(data), maybe_xhtml=True, keep_doctype=False, sanitize_names=True)
     # Check that the asinine HTML 5 algorithm did not result in a tree with
diff --git a/src/calibre/ebooks/oeb/polish/cascade.py b/src/calibre/ebooks/oeb/polish/cascade.py
index 5f71b31074..c6b6bc97d0 100644
--- a/src/calibre/ebooks/oeb/polish/cascade.py
+++ b/src/calibre/ebooks/oeb/polish/cascade.py
@@ -4,20 +4,21 @@
 
 import re
 from collections import defaultdict, namedtuple
-from css_parser.css import CSSRule, CSSStyleSheet, Property
 from functools import partial
 from itertools import count
 from operator import itemgetter
 
+from css_parser.css import CSSRule, CSSStyleSheet, Property
+from css_selectors import INAPPROPRIATE_PSEUDO_CLASSES, Select, SelectorError
+from tinycss.fonts3 import parse_font_family, serialize_font_family
+
 from calibre import as_unicode
 from calibre.ebooks.css_transform_rules import all_properties
 from calibre.ebooks.oeb.base import OEB_STYLES, XHTML, css_text
 from calibre.ebooks.oeb.normalize_css import DEFAULTS, normalizers
 from calibre.ebooks.oeb.stylizer import INHERITED, media_ok
 from calibre.utils.resources import get_path as P
-from css_selectors import INAPPROPRIATE_PSEUDO_CLASSES, Select, SelectorError
 from polyglot.builtins import iteritems, itervalues
-from tinycss.fonts3 import parse_font_family, serialize_font_family
 
 _html_css_stylesheet = None
 
diff --git a/src/calibre/ebooks/oeb/polish/check/base.py b/src/calibre/ebooks/oeb/polish/check/base.py
index 0af5d4fe61..76012fdc2f 100644
--- a/src/calibre/ebooks/oeb/polish/check/base.py
+++ b/src/calibre/ebooks/oeb/polish/check/base.py
@@ -4,9 +4,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from multiprocessing.pool import ThreadPool
-from functools import partial
 from contextlib import closing
+from functools import partial
+from multiprocessing.pool import ThreadPool
 
 from calibre import detect_ncpus as cpu_count
 
diff --git a/src/calibre/ebooks/oeb/polish/check/css.py b/src/calibre/ebooks/oeb/polish/check/css.py
index df0d621479..dfcb791f52 100644
--- a/src/calibre/ebooks/oeb/polish/check/css.py
+++ b/src/calibre/ebooks/oeb/polish/check/css.py
@@ -7,10 +7,12 @@ import numbers
 import sys
 from collections import namedtuple
 from itertools import repeat
+
 from qt.core import QApplication, QEventLoop, pyqtSignal, sip
 from qt.webengine import QWebEnginePage, QWebEngineProfile, QWebEngineScript
 
-from calibre import detect_ncpus as cpu_count, prints
+from calibre import detect_ncpus as cpu_count
+from calibre import prints
 from calibre.ebooks.oeb.polish.check.base import ERROR, WARN, BaseError
 from calibre.gui2 import must_use_qt
 from calibre.utils.resources import get_path as P
diff --git a/src/calibre/ebooks/oeb/polish/check/fonts.py b/src/calibre/ebooks/oeb/polish/check/fonts.py
index 7bfb4854be..eb42873ff2 100644
--- a/src/calibre/ebooks/oeb/polish/check/fonts.py
+++ b/src/calibre/ebooks/oeb/polish/check/fonts.py
@@ -5,15 +5,15 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from css_parser.css import CSSRule
+from tinycss.fonts3 import parse_font_family
 
 from calibre import force_unicode
 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES
-from calibre.ebooks.oeb.polish.check.base import BaseError, WARN
-from calibre.ebooks.oeb.polish.utils import OEB_FONTS
-from calibre.ebooks.oeb.polish.pretty import pretty_script_or_style
+from calibre.ebooks.oeb.polish.check.base import WARN, BaseError
 from calibre.ebooks.oeb.polish.fonts import change_font_in_declaration
-from calibre.utils.fonts.utils import get_all_font_names, is_font_embeddable, UnsupportedFont
-from tinycss.fonts3 import parse_font_family
+from calibre.ebooks.oeb.polish.pretty import pretty_script_or_style
+from calibre.ebooks.oeb.polish.utils import OEB_FONTS
+from calibre.utils.fonts.utils import UnsupportedFont, get_all_font_names, is_font_embeddable
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/oeb/polish/check/images.py b/src/calibre/ebooks/oeb/polish/check/images.py
index 47e82fb153..641f7c903b 100644
--- a/src/calibre/ebooks/oeb/polish/check/images.py
+++ b/src/calibre/ebooks/oeb/polish/check/images.py
@@ -5,10 +5,11 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from io import BytesIO
+
 from PIL import Image
 
 from calibre import as_unicode
-from calibre.ebooks.oeb.polish.check.base import BaseError, WARN
+from calibre.ebooks.oeb.polish.check.base import WARN, BaseError
 from calibre.ebooks.oeb.polish.check.parsing import EmptyFile
 from polyglot.builtins import error_message
 
@@ -32,6 +33,7 @@ class CMYKImage(BaseError):
 
     def __call__(self, container):
         from qt.core import QImage
+
         from calibre.gui2 import pixmap_to_data
         ext = container.mime_map[self.name].split('/')[-1].upper()
         if ext == 'JPG':
diff --git a/src/calibre/ebooks/oeb/polish/check/links.py b/src/calibre/ebooks/oeb/polish/check/links.py
index 4b48f62eae..de558d997f 100644
--- a/src/calibre/ebooks/oeb/polish/check/links.py
+++ b/src/calibre/ebooks/oeb/polish/check/links.py
@@ -9,15 +9,15 @@ from collections import defaultdict
 from threading import Thread
 
 from calibre import browser
-from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, urlunquote, XHTML_MIME
+from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, XHTML_MIME, urlunquote
+from calibre.ebooks.oeb.polish.check.base import ERROR, INFO, WARN, BaseError
+from calibre.ebooks.oeb.polish.cover import get_raster_cover_name
 from calibre.ebooks.oeb.polish.parsing import parse_html5
 from calibre.ebooks.oeb.polish.replace import remove_links_to
-from calibre.ebooks.oeb.polish.cover import get_raster_cover_name
-from calibre.ebooks.oeb.polish.utils import guess_type, actual_case_for_name, corrected_case_for_name, OEB_FONTS
-from calibre.ebooks.oeb.polish.check.base import BaseError, WARN, INFO, ERROR
+from calibre.ebooks.oeb.polish.utils import OEB_FONTS, actual_case_for_name, corrected_case_for_name, guess_type
 from polyglot.builtins import iteritems, itervalues
+from polyglot.queue import Empty, Queue
 from polyglot.urllib import urlparse
-from polyglot.queue import Queue, Empty
 
 
 class BadLink(BaseError):
diff --git a/src/calibre/ebooks/oeb/polish/check/main.py b/src/calibre/ebooks/oeb/polish/check/main.py
index dd7fdc6092..2aa7ad6095 100644
--- a/src/calibre/ebooks/oeb/polish/check/main.py
+++ b/src/calibre/ebooks/oeb/polish/check/main.py
@@ -10,13 +10,17 @@ from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES
 from calibre.ebooks.oeb.polish.check.base import WARN, run_checkers
 from calibre.ebooks.oeb.polish.check.fonts import check_fonts
 from calibre.ebooks.oeb.polish.check.images import check_raster_images
-from calibre.ebooks.oeb.polish.check.links import (
-    check_link_destinations, check_links, check_mimetypes,
-)
+from calibre.ebooks.oeb.polish.check.links import check_link_destinations, check_links, check_mimetypes
 from calibre.ebooks.oeb.polish.check.opf import check_opf
 from calibre.ebooks.oeb.polish.check.parsing import (
-    EmptyFile, check_encoding_declarations, check_filenames, check_html_size, check_ids,
-    check_markup, check_xml_parsing, fix_style_tag,
+    EmptyFile,
+    check_encoding_declarations,
+    check_filenames,
+    check_html_size,
+    check_ids,
+    check_markup,
+    check_xml_parsing,
+    fix_style_tag,
 )
 from calibre.ebooks.oeb.polish.cover import is_raster_image
 from calibre.ebooks.oeb.polish.utils import guess_type
diff --git a/src/calibre/ebooks/oeb/polish/check/opf.py b/src/calibre/ebooks/oeb/polish/check/opf.py
index 9fc8f32bd1..0c977b75fa 100644
--- a/src/calibre/ebooks/oeb/polish/check/opf.py
+++ b/src/calibre/ebooks/oeb/polish/check/opf.py
@@ -7,10 +7,10 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from lxml import etree
 
 from calibre import prepare_string_for_xml as xml
-from calibre.ebooks.oeb.polish.check.base import BaseError, WARN
+from calibre.ebooks.oeb.base import DC, DC11_NS, OPF, OPF2_NS, XHTML_MIME
+from calibre.ebooks.oeb.polish.check.base import WARN, BaseError
 from calibre.ebooks.oeb.polish.toc import find_existing_nav_toc, parse_nav
 from calibre.ebooks.oeb.polish.utils import guess_type
-from calibre.ebooks.oeb.base import OPF, OPF2_NS, DC, DC11_NS, XHTML_MIME
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/oeb/polish/check/parsing.py b/src/calibre/ebooks/oeb/polish/check/parsing.py
index 029ca25ff8..0961fb2253 100644
--- a/src/calibre/ebooks/oeb/polish/check/parsing.py
+++ b/src/calibre/ebooks/oeb/polish/check/parsing.py
@@ -5,6 +5,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
+
 from lxml.etree import XMLSyntaxError
 
 from calibre import human_readable, prepare_string_for_xml
diff --git a/src/calibre/ebooks/oeb/polish/container.py b/src/calibre/ebooks/oeb/polish/container.py
index 972bedbee7..fd8204cb8c 100644
--- a/src/calibre/ebooks/oeb/polish/container.py
+++ b/src/calibre/ebooks/oeb/polish/container.py
@@ -12,37 +12,41 @@ import sys
 import unicodedata
 import uuid
 from collections import defaultdict
-from css_parser import getUrls, replaceUrls
 from io import BytesIO
 from itertools import count
 
+from css_parser import getUrls, replaceUrls
+
 from calibre import CurrentDir, walk
 from calibre.constants import iswindows
 from calibre.customize.ui import plugin_for_input_format, plugin_for_output_format
 from calibre.ebooks import escape_xpath_attr
 from calibre.ebooks.chardet import xml_to_unicode
-from calibre.ebooks.conversion.plugins.epub_input import (
-    ADOBE_OBFUSCATION, IDPF_OBFUSCATION, decrypt_font_data
-)
-from calibre.ebooks.conversion.preprocess import (
-    CSSPreProcessor as cssp, HTMLPreProcessor
-)
-from calibre.ebooks.metadata.opf3 import (
-    CALIBRE_PREFIX, ensure_prefix, items_with_property, read_prefixes
-)
+from calibre.ebooks.conversion.plugins.epub_input import ADOBE_OBFUSCATION, IDPF_OBFUSCATION, decrypt_font_data
+from calibre.ebooks.conversion.preprocess import CSSPreProcessor as cssp
+from calibre.ebooks.conversion.preprocess import HTMLPreProcessor
+from calibre.ebooks.metadata.opf3 import CALIBRE_PREFIX, ensure_prefix, items_with_property, read_prefixes
 from calibre.ebooks.metadata.utils import parse_opf_version
 from calibre.ebooks.mobi import MobiError
 from calibre.ebooks.mobi.reader.headers import MetadataHeader
 from calibre.ebooks.oeb.base import (
-    DC11_NS, OEB_DOCS, OEB_STYLES, OPF, OPF2_NS, Manifest, itercsslinks, iterlinks,
-    rewrite_links, serialize, urlquote, urlunquote
+    DC11_NS,
+    OEB_DOCS,
+    OEB_STYLES,
+    OPF,
+    OPF2_NS,
+    Manifest,
+    itercsslinks,
+    iterlinks,
+    rewrite_links,
+    serialize,
+    urlquote,
+    urlunquote,
 )
 from calibre.ebooks.oeb.parse_utils import NotHTML, parse_html
 from calibre.ebooks.oeb.polish.errors import DRMError, InvalidBook
 from calibre.ebooks.oeb.polish.parsing import parse as parse_html_tweak
-from calibre.ebooks.oeb.polish.utils import (
-    CommentFinder, PositionFinder, adjust_mime_for_epub, guess_type, parse_css, OEB_FONTS
-)
+from calibre.ebooks.oeb.polish.utils import OEB_FONTS, CommentFinder, PositionFinder, adjust_mime_for_epub, guess_type, parse_css
 from calibre.ptempfile import PersistentTemporaryDirectory, PersistentTemporaryFile
 from calibre.utils.filenames import hardlink_file, nlinks_file, retry_on_fail
 from calibre.utils.ipc.simple_worker import WorkerError, fork_job
diff --git a/src/calibre/ebooks/oeb/polish/cover.py b/src/calibre/ebooks/oeb/polish/cover.py
index 3b9c94f969..3e34c15aa7 100644
--- a/src/calibre/ebooks/oeb/polish/cover.py
+++ b/src/calibre/ebooks/oeb/polish/cover.py
@@ -2,10 +2,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import shutil, re, os
+import os
+import re
+import shutil
 
-from calibre.ebooks.oeb.base import OPF, OEB_DOCS, XPath, XLINK, xml2text
-from calibre.ebooks.oeb.polish.replace import replace_links, get_recommended_folders
+from calibre.ebooks.oeb.base import OEB_DOCS, OPF, XLINK, XPath, xml2text
+from calibre.ebooks.oeb.polish.replace import get_recommended_folders, replace_links
 from calibre.utils.imghdr import identify
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/ebooks/oeb/polish/create.py b/src/calibre/ebooks/oeb/polish/create.py
index 9645aa71b9..c1c9900917 100644
--- a/src/calibre/ebooks/oeb/polish/create.py
+++ b/src/calibre/ebooks/oeb/polish/create.py
@@ -6,6 +6,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 import sys
+
 from lxml import etree
 
 from calibre import CurrentDir, prepare_string_for_xml
diff --git a/src/calibre/ebooks/oeb/polish/css.py b/src/calibre/ebooks/oeb/polish/css.py
index 37db8222f5..0047229665 100644
--- a/src/calibre/ebooks/oeb/polish/css.py
+++ b/src/calibre/ebooks/oeb/polish/css.py
@@ -6,19 +6,19 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 from collections import defaultdict
-from css_parser.css import CSSRule, CSSStyleDeclaration
 from functools import partial
 from operator import itemgetter
 
+from css_parser.css import CSSRule, CSSStyleDeclaration
+from css_selectors import Select, SelectorError, SelectorSyntaxError, parse
+
 from calibre import force_unicode
 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, XHTML, css_text
 from calibre.ebooks.oeb.normalize_css import normalize_filter_css, normalizers
-from calibre.ebooks.oeb.polish.pretty import (
-    pretty_script_or_style, pretty_xml_tree, serialize,
-)
-from calibre.utils.icu import lower as icu_lower, numeric_sort_key
+from calibre.ebooks.oeb.polish.pretty import pretty_script_or_style, pretty_xml_tree, serialize
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import numeric_sort_key
 from calibre.utils.localization import ngettext
-from css_selectors import Select, SelectorError, SelectorSyntaxError, parse
 from polyglot.builtins import iteritems, itervalues
 from polyglot.functools import lru_cache
 
diff --git a/src/calibre/ebooks/oeb/polish/download.py b/src/calibre/ebooks/oeb/polish/download.py
index 26de19e1ef..ff3c782382 100644
--- a/src/calibre/ebooks/oeb/polish/download.py
+++ b/src/calibre/ebooks/oeb/polish/download.py
@@ -14,7 +14,8 @@ from io import BytesIO
 from multiprocessing.dummy import Pool
 from tempfile import NamedTemporaryFile
 
-from calibre import as_unicode, browser, sanitize_file_name as sanitize_file_name_base
+from calibre import as_unicode, browser
+from calibre import sanitize_file_name as sanitize_file_name_base
 from calibre.constants import iswindows
 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, barename, iterlinks
 from calibre.ebooks.oeb.polish.utils import guess_type
diff --git a/src/calibre/ebooks/oeb/polish/embed.py b/src/calibre/ebooks/oeb/polish/embed.py
index 3904bd18d3..164f43d4bd 100644
--- a/src/calibre/ebooks/oeb/polish/embed.py
+++ b/src/calibre/ebooks/oeb/polish/embed.py
@@ -6,6 +6,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import sys
+
 from lxml import etree
 
 from calibre import prints
diff --git a/src/calibre/ebooks/oeb/polish/fonts.py b/src/calibre/ebooks/oeb/polish/fonts.py
index 237f4df3d6..28bd209eb9 100644
--- a/src/calibre/ebooks/oeb/polish/fonts.py
+++ b/src/calibre/ebooks/oeb/polish/fonts.py
@@ -4,10 +4,11 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
+from tinycss.fonts3 import parse_font, parse_font_family, serialize_font, serialize_font_family
+
 from calibre.ebooks.oeb.base import css_text
-from calibre.ebooks.oeb.polish.container import OEB_STYLES, OEB_DOCS
 from calibre.ebooks.oeb.normalize_css import normalize_font
-from tinycss.fonts3 import parse_font_family, parse_font, serialize_font_family, serialize_font
+from calibre.ebooks.oeb.polish.container import OEB_DOCS, OEB_STYLES
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/oeb/polish/images.py b/src/calibre/ebooks/oeb/polish/images.py
index f927b9819c..34ab4d4615 100644
--- a/src/calibre/ebooks/oeb/polish/images.py
+++ b/src/calibre/ebooks/oeb/polish/images.py
@@ -44,9 +44,7 @@ class Worker(Thread):
                 self.queue.task_done()
 
     def compress(self, name, path, mime_type):
-        from calibre.utils.img import (
-            encode_jpeg, encode_webp, optimize_jpeg, optimize_png, optimize_webp,
-        )
+        from calibre.utils.img import encode_jpeg, encode_webp, optimize_jpeg, optimize_png, optimize_webp
         if 'png' in mime_type:
             func = optimize_png
         elif 'webp' in mime_type:
diff --git a/src/calibre/ebooks/oeb/polish/import_book.py b/src/calibre/ebooks/oeb/polish/import_book.py
index 8664467574..dedd51dbe3 100644
--- a/src/calibre/ebooks/oeb/polish/import_book.py
+++ b/src/calibre/ebooks/oeb/polish/import_book.py
@@ -4,13 +4,13 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, sys
+import os
+import sys
 
-from calibre.ptempfile import TemporaryDirectory
 from calibre.ebooks.conversion.plumber import Plumber
-from calibre.ebooks.oeb.polish.container import Container, OEB_DOCS, OEB_STYLES
 from calibre.ebooks.epub import initialize_container
-
+from calibre.ebooks.oeb.polish.container import OEB_DOCS, OEB_STYLES, Container
+from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.logging import default_log
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/ebooks/oeb/polish/jacket.py b/src/calibre/ebooks/oeb/polish/jacket.py
index d5eee3514e..272315b6cd 100644
--- a/src/calibre/ebooks/oeb/polish/jacket.py
+++ b/src/calibre/ebooks/oeb/polish/jacket.py
@@ -7,9 +7,10 @@ __docformat__ = 'restructuredtext en'
 
 from calibre.customize.ui import output_profiles
 from calibre.ebooks.conversion.config import load_defaults
-from calibre.ebooks.oeb.base import XPath, OPF
+from calibre.ebooks.oeb.base import OPF, XPath
 from calibre.ebooks.oeb.polish.cover import find_cover_page
-from calibre.ebooks.oeb.transforms.jacket import render_jacket as render, referenced_images
+from calibre.ebooks.oeb.transforms.jacket import referenced_images
+from calibre.ebooks.oeb.transforms.jacket import render_jacket as render
 
 
 def render_jacket(container, jacket):
diff --git a/src/calibre/ebooks/oeb/polish/main.py b/src/calibre/ebooks/oeb/polish/main.py
index d445a959e0..fd32b77c4d 100644
--- a/src/calibre/ebooks/oeb/polish/main.py
+++ b/src/calibre/ebooks/oeb/polish/main.py
@@ -5,22 +5,23 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, sys, time
+import re
+import sys
+import time
 from collections import namedtuple
 from functools import partial
 
 from calibre.ebooks.oeb.polish.container import get_container
-from calibre.ebooks.oeb.polish.stats import StatsCollector
-from calibre.ebooks.oeb.polish.subset import subset_all_fonts, iter_subsettable_fonts
-from calibre.ebooks.oeb.polish.images import compress_images
-from calibre.ebooks.oeb.polish.upgrade import upgrade_book
-from calibre.ebooks.oeb.polish.embed import embed_all_fonts
 from calibre.ebooks.oeb.polish.cover import set_cover
-from calibre.ebooks.oeb.polish.replace import smarten_punctuation
-from calibre.ebooks.oeb.polish.jacket import (
-    replace_jacket, add_or_replace_jacket, find_existing_jacket, remove_jacket)
 from calibre.ebooks.oeb.polish.css import remove_unused_css
-from calibre.ebooks.oeb.polish.hyphenation import remove_soft_hyphens, add_soft_hyphens
+from calibre.ebooks.oeb.polish.embed import embed_all_fonts
+from calibre.ebooks.oeb.polish.hyphenation import add_soft_hyphens, remove_soft_hyphens
+from calibre.ebooks.oeb.polish.images import compress_images
+from calibre.ebooks.oeb.polish.jacket import add_or_replace_jacket, find_existing_jacket, remove_jacket, replace_jacket
+from calibre.ebooks.oeb.polish.replace import smarten_punctuation
+from calibre.ebooks.oeb.polish.stats import StatsCollector
+from calibre.ebooks.oeb.polish.subset import iter_subsettable_fonts, subset_all_fonts
+from calibre.ebooks.oeb.polish.upgrade import upgrade_book
 from calibre.utils.logging import Log
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/ebooks/oeb/polish/parsing.py b/src/calibre/ebooks/oeb/polish/parsing.py
index 5f47df916c..033e84268f 100644
--- a/src/calibre/ebooks/oeb/polish/parsing.py
+++ b/src/calibre/ebooks/oeb/polish/parsing.py
@@ -6,13 +6,13 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 
-from lxml.etree import Element as LxmlElement
 import html5_parser
+from lxml.etree import Element as LxmlElement
 
 from calibre import xml_replace_entities
-from calibre.utils.xml_parse import safe_xml_fromstring
-from calibre.ebooks.chardet import xml_to_unicode, strip_encoding_declarations
+from calibre.ebooks.chardet import strip_encoding_declarations, xml_to_unicode
 from calibre.utils.cleantext import clean_xml_chars
+from calibre.utils.xml_parse import safe_xml_fromstring
 
 XHTML_NS     = 'http://www.w3.org/1999/xhtml'
 
diff --git a/src/calibre/ebooks/oeb/polish/pretty.py b/src/calibre/ebooks/oeb/polish/pretty.py
index 8b1dd2942a..c30a31c7ff 100644
--- a/src/calibre/ebooks/oeb/polish/pretty.py
+++ b/src/calibre/ebooks/oeb/polish/pretty.py
@@ -5,16 +5,14 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import textwrap
-from polyglot.builtins import iteritems
 
 # from lxml.etree import Element
-
 from calibre import force_unicode
-from calibre.ebooks.oeb.base import (
-    serialize, OEB_DOCS, barename, OEB_STYLES, XPNSMAP, XHTML, SVG)
+from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, SVG, XHTML, XPNSMAP, barename, serialize
 from calibre.ebooks.oeb.polish.container import OPF_NAMESPACES
 from calibre.ebooks.oeb.polish.utils import guess_type
 from calibre.utils.icu import sort_key
+from polyglot.builtins import iteritems
 
 
 def isspace(x):
diff --git a/src/calibre/ebooks/oeb/polish/replace.py b/src/calibre/ebooks/oeb/polish/replace.py
index efc09be273..b3d6619693 100644
--- a/src/calibre/ebooks/oeb/polish/replace.py
+++ b/src/calibre/ebooks/oeb/polish/replace.py
@@ -5,16 +5,19 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import codecs, shutil, os, posixpath
-from polyglot.builtins import iteritems, itervalues
-from functools import partial
+import codecs
+import os
+import posixpath
+import shutil
 from collections import Counter, defaultdict
+from functools import partial
 
 from calibre import sanitize_file_name
 from calibre.ebooks.chardet import strip_encoding_declarations
 from calibre.ebooks.oeb.base import css_text
 from calibre.ebooks.oeb.polish.css import iter_declarations, remove_property_value
 from calibre.ebooks.oeb.polish.utils import extract
+from polyglot.builtins import iteritems, itervalues
 from polyglot.urllib import urlparse, urlunparse
 
 
@@ -229,8 +232,8 @@ def replace_file(container, name, path, basename, force_mt=None):
 
 
 def mt_to_category(container, mt):
-    from calibre.ebooks.oeb.polish.utils import guess_type, OEB_FONTS
     from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES
+    from calibre.ebooks.oeb.polish.utils import OEB_FONTS, guess_type
     if mt in OEB_DOCS:
         category = 'text'
     elif mt in OEB_STYLES:
@@ -345,7 +348,7 @@ def remove_links_in_declaration(href_to_name, style, predicate):
 def remove_links_to(container, predicate):
     ''' predicate must be a function that takes the arguments (name, href,
     fragment=None) and returns True iff the link should be removed '''
-    from calibre.ebooks.oeb.base import iterlinks, OEB_DOCS, OEB_STYLES, XPath, XHTML
+    from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, XHTML, XPath, iterlinks
     stylepath = XPath('//h:style')
     styleattrpath = XPath('//*[@style]')
     changed = set()
diff --git a/src/calibre/ebooks/oeb/polish/report.py b/src/calibre/ebooks/oeb/polish/report.py
index 6cf8bda5bd..0af77ae56b 100644
--- a/src/calibre/ebooks/oeb/polish/report.py
+++ b/src/calibre/ebooks/oeb/polish/report.py
@@ -4,18 +4,22 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import posixpath, os, time, types
-from collections import namedtuple, defaultdict
+import os
+import posixpath
+import time
+import types
+from collections import defaultdict, namedtuple
 from itertools import chain
 
-from calibre import prepare_string_for_xml, force_unicode
+from css_selectors import Select, SelectorError
+
+from calibre import force_unicode, prepare_string_for_xml
 from calibre.ebooks.oeb.base import XPath, xml2text
 from calibre.ebooks.oeb.polish.container import OEB_DOCS, OEB_STYLES
+from calibre.ebooks.oeb.polish.spell import count_all_chars, get_all_words
 from calibre.ebooks.oeb.polish.utils import OEB_FONTS
-from calibre.ebooks.oeb.polish.spell import get_all_words, count_all_chars
 from calibre.utils.icu import numeric_sort_key, safe_chr
 from calibre.utils.imghdr import identify
-from css_selectors import Select, SelectorError
 from polyglot.builtins import iteritems
 
 File = namedtuple('File', 'name dir basename size category word_count')
@@ -234,7 +238,7 @@ ClassElement = namedtuple('ClassElement', 'name line_number text_on_line tag mat
 
 def css_data(container, book_locale, result_data, *args):
     import tinycss
-    from tinycss.css21 import RuleSet, ImportRule
+    from tinycss.css21 import ImportRule, RuleSet
 
     def css_rules(file_name, rules, sourceline=0):
         ans = []
diff --git a/src/calibre/ebooks/oeb/polish/spell.py b/src/calibre/ebooks/oeb/polish/spell.py
index 92b3f4d015..f33f7ccfd9 100644
--- a/src/calibre/ebooks/oeb/polish/spell.py
+++ b/src/calibre/ebooks/oeb/polish/spell.py
@@ -5,15 +5,15 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
-from collections import defaultdict, Counter
+from collections import Counter, defaultdict
 
 from calibre import replace_entities
-from calibre.spell.break_iterator import split_into_words, index_of
-from calibre.spell.dictionary import parse_lang_code
 from calibre.ebooks.oeb.base import barename
 from calibre.ebooks.oeb.polish.container import OPF_NAMESPACES, get_container
 from calibre.ebooks.oeb.polish.parsing import parse
-from calibre.ebooks.oeb.polish.toc import find_existing_ncx_toc, find_existing_nav_toc
+from calibre.ebooks.oeb.polish.toc import find_existing_nav_toc, find_existing_ncx_toc
+from calibre.spell.break_iterator import index_of, split_into_words
+from calibre.spell.dictionary import parse_lang_code
 from calibre.utils.icu import ord_string
 from polyglot.builtins import iteritems
 
@@ -404,7 +404,8 @@ def undo_replace_word(container, undo_cache):
 
 if __name__ == '__main__':
     import pprint
-    from calibre.gui2.tweak_book import set_book_locale, dictionaries
+
+    from calibre.gui2.tweak_book import dictionaries, set_book_locale
     container = get_container(sys.argv[-1], tweak_mode=True)
     set_book_locale(container.mi.language)
     pprint.pprint(get_all_words(container, dictionaries.default_locale))
diff --git a/src/calibre/ebooks/oeb/polish/split.py b/src/calibre/ebooks/oeb/polish/split.py
index 47151d20f4..7567ac6fdf 100644
--- a/src/calibre/ebooks/oeb/polish/split.py
+++ b/src/calibre/ebooks/oeb/polish/split.py
@@ -4,14 +4,15 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import copy, os, re
-from polyglot.builtins import string_or_bytes
+import copy
+import os
+import re
 
-from calibre.ebooks.oeb.base import barename, XPNSMAP, XPath, OPF, XHTML, OEB_DOCS
+from calibre.ebooks.oeb.base import OEB_DOCS, OPF, XHTML, XPNSMAP, XPath, barename
 from calibre.ebooks.oeb.polish.errors import MalformedMarkup
-from calibre.ebooks.oeb.polish.toc import node_from_loc
 from calibre.ebooks.oeb.polish.replace import LinkRebaser
-from polyglot.builtins import iteritems
+from calibre.ebooks.oeb.polish.toc import node_from_loc
+from polyglot.builtins import iteritems, string_or_bytes
 from polyglot.urllib import urlparse
 
 
diff --git a/src/calibre/ebooks/oeb/polish/stats.py b/src/calibre/ebooks/oeb/polish/stats.py
index 91b302ecb2..2cd6fd4d36 100644
--- a/src/calibre/ebooks/oeb/polish/stats.py
+++ b/src/calibre/ebooks/oeb/polish/stats.py
@@ -5,18 +5,19 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import regex
 import sys
 from functools import partial
+
+import regex
 from lxml.etree import tostring
+from tinycss.fonts3 import parse_font_family
 
 from calibre.ebooks.oeb.base import XHTML, css_text
 from calibre.ebooks.oeb.polish.cascade import iterdeclaration, iterrules, resolve_styles
-from calibre.utils.icu import (
-    lower as icu_lower, ord_string, safe_chr, upper as icu_upper,
-)
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import ord_string, safe_chr
+from calibre.utils.icu import upper as icu_upper
 from polyglot.builtins import iteritems, itervalues
-from tinycss.fonts3 import parse_font_family
 
 
 def normalize_font_properties(font):
diff --git a/src/calibre/ebooks/oeb/polish/tests/base.py b/src/calibre/ebooks/oeb/polish/tests/base.py
index fcc21004a4..f741142b7a 100644
--- a/src/calibre/ebooks/oeb/polish/tests/base.py
+++ b/src/calibre/ebooks/oeb/polish/tests/base.py
@@ -12,7 +12,8 @@ import calibre.ebooks.oeb.polish.container as pc
 from calibre import CurrentDir
 from calibre.ptempfile import PersistentTemporaryDirectory, TemporaryDirectory
 from calibre.utils.logging import DevNull
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/oeb/polish/tests/cascade.py b/src/calibre/ebooks/oeb/polish/tests/cascade.py
index ec47d9911b..153c3c447e 100644
--- a/src/calibre/ebooks/oeb/polish/tests/cascade.py
+++ b/src/calibre/ebooks/oeb/polish/tests/cascade.py
@@ -4,18 +4,17 @@
 __license__ = 'GPL v3'
 __copyright__ = '2016, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from css_parser import parseStyle
 from functools import partial
 
+from css_parser import parseStyle
+
 from calibre.constants import iswindows
 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES
 from calibre.ebooks.oeb.polish.cascade import DEFAULTS, iterrules, resolve_styles
 from calibre.ebooks.oeb.polish.container import ContainerBase, href_to_name
 from calibre.ebooks.oeb.polish.css import remove_property_value
 from calibre.ebooks.oeb.polish.embed import find_matching_font
-from calibre.ebooks.oeb.polish.stats import (
-    StatsCollector, font_keys, normalize_font_properties, prepare_font_rule,
-)
+from calibre.ebooks.oeb.polish.stats import StatsCollector, font_keys, normalize_font_properties, prepare_font_rule
 from calibre.ebooks.oeb.polish.tests.base import BaseTest
 from calibre.utils.icu import lower as icu_lower
 from calibre.utils.logging import Log, Stream
diff --git a/src/calibre/ebooks/oeb/polish/tests/container.py b/src/calibre/ebooks/oeb/polish/tests/container.py
index 7f4ed12946..0f58c40735 100644
--- a/src/calibre/ebooks/oeb/polish/tests/container.py
+++ b/src/calibre/ebooks/oeb/polish/tests/container.py
@@ -9,14 +9,11 @@ import subprocess
 from zipfile import ZipFile
 
 from calibre import CurrentDir
-from calibre.ebooks.oeb.polish.container import (
-    OCF_NS, clone_container, get_container as _gc,
-)
+from calibre.ebooks.oeb.polish.container import OCF_NS, clone_container
+from calibre.ebooks.oeb.polish.container import get_container as _gc
 from calibre.ebooks.oeb.polish.replace import rationalize_folders, rename_files
 from calibre.ebooks.oeb.polish.split import merge, split
-from calibre.ebooks.oeb.polish.tests.base import (
-    BaseTest, get_simple_book, get_split_book,
-)
+from calibre.ebooks.oeb.polish.tests.base import BaseTest, get_simple_book, get_split_book
 from calibre.ptempfile import TemporaryDirectory, TemporaryFile
 from calibre.utils.filenames import nlinks_file
 from calibre.utils.resources import get_path as P
@@ -202,9 +199,7 @@ class ContainerTests(BaseTest):
 
     def test_actual_case(self):
         ' Test getting the actual case for files from names on case insensitive filesystems '
-        from calibre.ebooks.oeb.polish.utils import (
-            actual_case_for_name, corrected_case_for_name,
-        )
+        from calibre.ebooks.oeb.polish.utils import actual_case_for_name, corrected_case_for_name
         book = get_simple_book()
         c = get_container(book)
         name = 'f1/f2/added file.html'
diff --git a/src/calibre/ebooks/oeb/polish/tests/parsing.py b/src/calibre/ebooks/oeb/polish/tests/parsing.py
index 8f04f8a7d3..b65b697af0 100644
--- a/src/calibre/ebooks/oeb/polish/tests/parsing.py
+++ b/src/calibre/ebooks/oeb/polish/tests/parsing.py
@@ -6,13 +6,13 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
 
-from lxml import etree
 from html5lib.constants import cdataElements, rcdataElements
+from lxml import etree
 
-from calibre.ebooks.oeb.polish.tests.base import BaseTest
-from calibre.ebooks.oeb.polish.parsing import parse_html5 as parse
-from calibre.ebooks.oeb.base import XPath, XHTML_NS, SVG_NS, XLINK_NS
+from calibre.ebooks.oeb.base import SVG_NS, XHTML_NS, XLINK_NS, XPath
 from calibre.ebooks.oeb.parse_utils import html5_parse
+from calibre.ebooks.oeb.polish.parsing import parse_html5 as parse
+from calibre.ebooks.oeb.polish.tests.base import BaseTest
 from polyglot.builtins import iteritems
 
 
@@ -210,9 +210,11 @@ class ParsingTests(BaseTest):
 
 def timing():
     import sys
+
+    from html5lib import parse as vanilla
+
     from calibre.ebooks.chardet import xml_to_unicode
     from calibre.utils.monotonic import monotonic
-    from html5lib import parse as vanilla
     filename = sys.argv[-1]
     with open(filename, 'rb') as f:
         raw = f.read()
diff --git a/src/calibre/ebooks/oeb/polish/tests/structure.py b/src/calibre/ebooks/oeb/polish/tests/structure.py
index 912ea380ac..4b072d28d2 100644
--- a/src/calibre/ebooks/oeb/polish/tests/structure.py
+++ b/src/calibre/ebooks/oeb/polish/tests/structure.py
@@ -2,22 +2,22 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
+import os
+from functools import partial
 from io import BytesIO
 from itertools import count
-from functools import partial
-from zipfile import ZipFile, ZIP_STORED
-import os
-from calibre.ebooks.oeb.polish.tests.base import BaseTest
-from calibre.ebooks.oeb.polish.container import get_container
-from calibre.ebooks.oeb.polish.create import create_book
-from calibre.ebooks.oeb.polish.cover import (
-    find_cover_image, mark_as_cover, find_cover_page, mark_as_titlepage, clean_opf
-)
-from calibre.ebooks.oeb.polish.toc import get_toc, from_xpaths as toc_from_xpaths, get_landmarks
-from calibre.ebooks.oeb.polish.utils import guess_type
-from calibre.ebooks.oeb.base import OEB_DOCS
+from zipfile import ZIP_STORED, ZipFile
+
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.opf3 import CALIBRE_PREFIX
+from calibre.ebooks.oeb.base import OEB_DOCS
+from calibre.ebooks.oeb.polish.container import get_container
+from calibre.ebooks.oeb.polish.cover import clean_opf, find_cover_image, find_cover_page, mark_as_cover, mark_as_titlepage
+from calibre.ebooks.oeb.polish.create import create_book
+from calibre.ebooks.oeb.polish.tests.base import BaseTest
+from calibre.ebooks.oeb.polish.toc import from_xpaths as toc_from_xpaths
+from calibre.ebooks.oeb.polish.toc import get_landmarks, get_toc
+from calibre.ebooks.oeb.polish.utils import guess_type
 
 OPF_TEMPLATE = '''
 <package xmlns="http://www.idpf.org/2007/opf" version="{ver}" prefix="calibre: %s" unique-identifier="uid">
diff --git a/src/calibre/ebooks/oeb/polish/toc.py b/src/calibre/ebooks/oeb/polish/toc.py
index a6f51ea1b0..1147f26938 100644
--- a/src/calibre/ebooks/oeb/polish/toc.py
+++ b/src/calibre/ebooks/oeb/polish/toc.py
@@ -8,15 +8,13 @@ __docformat__ = 'restructuredtext en'
 import re
 from collections import Counter, OrderedDict
 from functools import partial
-from lxml import etree
-from lxml.builder import ElementMaker
 from operator import itemgetter
 
+from lxml import etree
+from lxml.builder import ElementMaker
+
 from calibre import __version__
-from calibre.ebooks.oeb.base import (
-    EPUB_NS, NCX, NCX_NS, OEB_DOCS, XHTML, XHTML_NS, XML, XML_NS, XPath, serialize,
-    uuid_id, xml2text,
-)
+from calibre.ebooks.oeb.base import EPUB_NS, NCX, NCX_NS, OEB_DOCS, XHTML, XHTML_NS, XML, XML_NS, XPath, serialize, uuid_id, xml2text
 from calibre.ebooks.oeb.polish.errors import MalformedMarkup
 from calibre.ebooks.oeb.polish.opf import get_book_language, set_guide_item
 from calibre.ebooks.oeb.polish.pretty import pretty_html_tree, pretty_xml_tree
diff --git a/src/calibre/ebooks/oeb/polish/upgrade.py b/src/calibre/ebooks/oeb/polish/upgrade.py
index d520066551..55846a12ad 100644
--- a/src/calibre/ebooks/oeb/polish/upgrade.py
+++ b/src/calibre/ebooks/oeb/polish/upgrade.py
@@ -4,17 +4,13 @@
 
 import sys
 
-from calibre.ebooks.conversion.plugins.epub_input import (
-    ADOBE_OBFUSCATION, IDPF_OBFUSCATION
-)
+from calibre.ebooks.conversion.plugins.epub_input import ADOBE_OBFUSCATION, IDPF_OBFUSCATION
 from calibre.ebooks.metadata.opf3 import XPath
 from calibre.ebooks.metadata.opf_2_to_3 import upgrade_metadata
 from calibre.ebooks.oeb.base import DC, EPUB_NS, OEB_DOCS, xpath
 from calibre.ebooks.oeb.parse_utils import ensure_namespace_prefixes
 from calibre.ebooks.oeb.polish.opf import get_book_language
-from calibre.ebooks.oeb.polish.toc import (
-    commit_nav_toc, find_existing_ncx_toc, get_landmarks, get_toc
-)
+from calibre.ebooks.oeb.polish.toc import commit_nav_toc, find_existing_ncx_toc, get_landmarks, get_toc
 from calibre.ebooks.oeb.polish.utils import OEB_FONTS
 from calibre.utils.short_uuid import uuid4
 
diff --git a/src/calibre/ebooks/oeb/polish/utils.py b/src/calibre/ebooks/oeb/polish/utils.py
index afd5e6b6cf..122aa3cb09 100644
--- a/src/calibre/ebooks/oeb/polish/utils.py
+++ b/src/calibre/ebooks/oeb/polish/utils.py
@@ -4,13 +4,14 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import re, os
+import os
+import re
 from bisect import bisect
 
-from calibre import guess_type as _guess_type, replace_entities
+from calibre import guess_type as _guess_type
+from calibre import replace_entities
 from calibre.utils.icu import upper as icu_upper
 
-
 BLOCK_TAG_NAMES = frozenset((
     'address', 'article', 'aside', 'blockquote', 'center', 'dir', 'fieldset',
     'isindex', 'menu', 'noframes', 'hgroup', 'noscript', 'pre', 'section',
@@ -160,7 +161,7 @@ class CommentFinder:
 
 
 def link_stylesheets(container, names, sheets, remove=False, mtype='text/css'):
-    from calibre.ebooks.oeb.base import XPath, XHTML
+    from calibre.ebooks.oeb.base import XHTML, XPath
     changed_names = set()
     snames = set(sheets)
     lp = XPath('//h:link[@href]')
@@ -221,6 +222,7 @@ def parse_css(data, fname='<string>', is_declaration=False, decode=None, log_lev
         import logging
         log_level = logging.WARNING
     from css_parser import CSSParser, log
+
     from calibre.ebooks.oeb.base import _css_logger
     log.setLevel(log_level)
     log.raiseExceptions = False
diff --git a/src/calibre/ebooks/oeb/reader.py b/src/calibre/ebooks/oeb/reader.py
index 740d12187b..005d63159f 100644
--- a/src/calibre/ebooks/oeb/reader.py
+++ b/src/calibre/ebooks/oeb/reader.py
@@ -13,15 +13,40 @@ import re
 import sys
 import uuid
 from collections import defaultdict
+
 from lxml import etree
 
 from calibre import guess_type, xml_replace_entities
 from calibre.constants import __appname__, __version__
 from calibre.ebooks.oeb.base import (
-    BINARY_MIME, COLLAPSE_RE, DC11_NS, DC_NSES, JPEG_MIME, MS_COVER_TYPE, NCX_MIME,
-    OEB_DOCS, OEB_IMAGES, OEB_STYLES, OPF, OPF1_NS, OPF2_NS, OPF2_NSMAP, PAGE_MAP_MIME,
-    SVG_MIME, XHTML_MIME, XMLDECL_RE, DirContainer, OEBBook, OEBError, XPath, barename,
-    iterlinks, namespace, urlnormalize, xml2text, xpath,
+    BINARY_MIME,
+    COLLAPSE_RE,
+    DC11_NS,
+    DC_NSES,
+    JPEG_MIME,
+    MS_COVER_TYPE,
+    NCX_MIME,
+    OEB_DOCS,
+    OEB_IMAGES,
+    OEB_STYLES,
+    OPF,
+    OPF1_NS,
+    OPF2_NS,
+    OPF2_NSMAP,
+    PAGE_MAP_MIME,
+    SVG_MIME,
+    XHTML_MIME,
+    XMLDECL_RE,
+    DirContainer,
+    OEBBook,
+    OEBError,
+    XPath,
+    barename,
+    iterlinks,
+    namespace,
+    urlnormalize,
+    xml2text,
+    xpath,
 )
 from calibre.ebooks.oeb.writer import OEBWriter
 from calibre.ptempfile import TemporaryDirectory
diff --git a/src/calibre/ebooks/oeb/stylizer.py b/src/calibre/ebooks/oeb/stylizer.py
index ce08fb6962..ff8178ab79 100644
--- a/src/calibre/ebooks/oeb/stylizer.py
+++ b/src/calibre/ebooks/oeb/stylizer.py
@@ -11,25 +11,23 @@ import numbers
 import os
 import re
 import unicodedata
-from css_parser import (
-    CSSParser, log as css_parser_log, parseString, parseStyle, profile as cssprofiles,
-    profiles, replaceUrls,
-)
-from css_parser.css import CSSFontFaceRule, CSSPageRule, CSSStyleRule, cssproperties
 from operator import itemgetter
 from weakref import WeakKeyDictionary
 from xml.dom import SyntaxErr as CSSSyntaxError
 
+from css_parser import CSSParser, parseString, parseStyle, profiles, replaceUrls
+from css_parser import log as css_parser_log
+from css_parser import profile as cssprofiles
+from css_parser.css import CSSFontFaceRule, CSSPageRule, CSSStyleRule, cssproperties
+from css_selectors import INAPPROPRIATE_PSEUDO_CLASSES, Select, SelectorError
+from tinycss.media3 import CSSMedia3Parser
+
 from calibre import as_unicode, force_unicode
 from calibre.ebooks import unit_convert
-from calibre.ebooks.oeb.base import (
-    CSS_MIME, OEB_STYLES, XHTML, XHTML_NS, urlnormalize, xpath,
-)
+from calibre.ebooks.oeb.base import CSS_MIME, OEB_STYLES, XHTML, XHTML_NS, urlnormalize, xpath
 from calibre.ebooks.oeb.normalize_css import DEFAULTS, normalizers
 from calibre.utils.resources import get_path as P
-from css_selectors import INAPPROPRIATE_PSEUDO_CLASSES, Select, SelectorError
 from polyglot.builtins import iteritems
-from tinycss.media3 import CSSMedia3Parser
 
 css_parser_log.setLevel(logging.WARN)
 
diff --git a/src/calibre/ebooks/oeb/transforms/data_url.py b/src/calibre/ebooks/oeb/transforms/data_url.py
index fedbf8a65c..ffd4101c5f 100644
--- a/src/calibre/ebooks/oeb/transforms/data_url.py
+++ b/src/calibre/ebooks/oeb/transforms/data_url.py
@@ -5,6 +5,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
+
 from calibre.ebooks.oeb.base import XPath, urlunquote
 from polyglot.builtins import as_bytes
 
diff --git a/src/calibre/ebooks/oeb/transforms/embed_fonts.py b/src/calibre/ebooks/oeb/transforms/embed_fonts.py
index a10d0d1813..3cb1740cf4 100644
--- a/src/calibre/ebooks/oeb/transforms/embed_fonts.py
+++ b/src/calibre/ebooks/oeb/transforms/embed_fonts.py
@@ -11,11 +11,11 @@ import css_parser
 from lxml import etree
 
 from calibre import guess_type
-from calibre.ebooks.oeb.base import XPath, CSS_MIME, XHTML
-from calibre.ebooks.oeb.transforms.subset import get_font_properties, find_font_face_rules, elem_style
-from calibre.utils.filenames import ascii_filename
-from calibre.utils.fonts.scanner import font_scanner, NoFonts
+from calibre.ebooks.oeb.base import CSS_MIME, XHTML, XPath
 from calibre.ebooks.oeb.polish.embed import font_key
+from calibre.ebooks.oeb.transforms.subset import elem_style, find_font_face_rules, get_font_properties
+from calibre.utils.filenames import ascii_filename
+from calibre.utils.fonts.scanner import NoFonts, font_scanner
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/oeb/transforms/flatcss.py b/src/calibre/ebooks/oeb/transforms/flatcss.py
index bfc29978a1..214e06e55a 100644
--- a/src/calibre/ebooks/oeb/transforms/flatcss.py
+++ b/src/calibre/ebooks/oeb/transforms/flatcss.py
@@ -6,18 +6,20 @@ CSS flattening transform.
 __license__   = 'GPL v3'
 __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
-import re, operator, math, numbers
+import math
+import numbers
+import operator
+import re
 from collections import defaultdict
 from xml.dom import SyntaxErr
 
-from lxml import etree
 import css_parser
 from css_parser.css import Property
+from lxml import etree
 
 from calibre import guess_type
 from calibre.ebooks import unit_convert
-from calibre.ebooks.oeb.base import (XHTML, XHTML_NS, CSS_MIME, OEB_STYLES, SVG_NS,
-        namespace, barename, XPath, css_text)
+from calibre.ebooks.oeb.base import CSS_MIME, OEB_STYLES, SVG_NS, XHTML, XHTML_NS, XPath, barename, css_text, namespace
 from calibre.ebooks.oeb.stylizer import Stylizer
 from calibre.utils.filenames import ascii_filename, ascii_text
 from calibre.utils.icu import numeric_sort_key
@@ -223,7 +225,7 @@ class CSSFlattener:
         body_font_family = None
         if not family:
             return body_font_family, efi
-        from calibre.utils.fonts.scanner import font_scanner, NoFonts
+        from calibre.utils.fonts.scanner import NoFonts, font_scanner
         from calibre.utils.fonts.utils import panose_to_css_generic_family
         try:
             faces = font_scanner.fonts_for_family(family)
diff --git a/src/calibre/ebooks/oeb/transforms/htmltoc.py b/src/calibre/ebooks/oeb/transforms/htmltoc.py
index 135e224b7f..38a6d69b33 100644
--- a/src/calibre/ebooks/oeb/transforms/htmltoc.py
+++ b/src/calibre/ebooks/oeb/transforms/htmltoc.py
@@ -5,9 +5,7 @@ HTML-TOC-adding transform.
 __license__   = 'GPL v3'
 __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
-from calibre.ebooks.oeb.base import (
-    CSS_MIME, XHTML, XHTML_MIME, XHTML_NS, XML, XPath, element,
-)
+from calibre.ebooks.oeb.base import CSS_MIME, XHTML, XHTML_MIME, XHTML_NS, XML, XPath, element
 from calibre.utils.localization import __
 
 __all__ = ['HTMLTOCAdder']
diff --git a/src/calibre/ebooks/oeb/transforms/jacket.py b/src/calibre/ebooks/oeb/transforms/jacket.py
index 91d21f7ab3..9e5932c191 100644
--- a/src/calibre/ebooks/oeb/transforms/jacket.py
+++ b/src/calibre/ebooks/oeb/transforms/jacket.py
@@ -17,9 +17,7 @@ from calibre.constants import iswindows
 from calibre.ebooks.chardet import strip_encoding_declarations
 from calibre.ebooks.metadata import fmt_sidx, rating_to_stars
 from calibre.ebooks.metadata.sources.identify import urls_from_identifiers
-from calibre.ebooks.oeb.base import (
-    XHTML, XHTML_NS, XPath, urldefrag, urlnormalize, xml2text,
-)
+from calibre.ebooks.oeb.base import XHTML, XHTML_NS, XPath, urldefrag, urlnormalize, xml2text
 from calibre.library.comments import comments_to_html, markdown
 from calibre.utils.config import tweaks
 from calibre.utils.date import as_local_time, format_date, is_date_undefined
diff --git a/src/calibre/ebooks/oeb/transforms/linearize_tables.py b/src/calibre/ebooks/oeb/transforms/linearize_tables.py
index 3578614dba..b3c05539e8 100644
--- a/src/calibre/ebooks/oeb/transforms/linearize_tables.py
+++ b/src/calibre/ebooks/oeb/transforms/linearize_tables.py
@@ -5,7 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.ebooks.oeb.base import OEB_DOCS, XPath, XHTML
+from calibre.ebooks.oeb.base import OEB_DOCS, XHTML, XPath
 
 
 class LinearizeTables:
diff --git a/src/calibre/ebooks/oeb/transforms/manglecase.py b/src/calibre/ebooks/oeb/transforms/manglecase.py
index c2f76239d2..7df2d9e330 100644
--- a/src/calibre/ebooks/oeb/transforms/manglecase.py
+++ b/src/calibre/ebooks/oeb/transforms/manglecase.py
@@ -9,9 +9,9 @@ from lxml import etree
 
 from calibre.ebooks.oeb.base import CSS_MIME, XHTML, XHTML_NS, namespace
 from calibre.ebooks.oeb.stylizer import Stylizer
-from calibre.utils.icu import (
-    lower as icu_lower, title_case as icu_title, upper as icu_upper,
-)
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import title_case as icu_title
+from calibre.utils.icu import upper as icu_upper
 from polyglot.builtins import string_or_bytes
 
 CASE_MANGLER_CSS = """
diff --git a/src/calibre/ebooks/oeb/transforms/metadata.py b/src/calibre/ebooks/oeb/transforms/metadata.py
index 12a3ce2dfa..bd99f0d0bf 100644
--- a/src/calibre/ebooks/oeb/transforms/metadata.py
+++ b/src/calibre/ebooks/oeb/transforms/metadata.py
@@ -5,9 +5,11 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, re
-from calibre.utils.date import isoformat, now
+import os
+import re
+
 from calibre import guess_type
+from calibre.utils.date import isoformat, now
 from polyglot.builtins import iteritems
 
 
@@ -166,9 +168,10 @@ class MergeMetadata:
         return id
 
     def remove_old_cover(self, cover_item, new_cover_href=None):
-        from calibre.ebooks.oeb.base import XPath, XLINK
         from lxml import etree
 
+        from calibre.ebooks.oeb.base import XLINK, XPath
+
         self.oeb.manifest.remove(cover_item)
 
         # Remove any references to the cover in the HTML
diff --git a/src/calibre/ebooks/oeb/transforms/page_margin.py b/src/calibre/ebooks/oeb/transforms/page_margin.py
index 07392d6c4a..7b49788e15 100644
--- a/src/calibre/ebooks/oeb/transforms/page_margin.py
+++ b/src/calibre/ebooks/oeb/transforms/page_margin.py
@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 import numbers
 from collections import Counter
 
-from calibre.ebooks.oeb.base import barename, XPath
+from calibre.ebooks.oeb.base import XPath, barename
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/oeb/transforms/rasterize.py b/src/calibre/ebooks/oeb/transforms/rasterize.py
index ae5459adb1..6b2d583cbc 100644
--- a/src/calibre/ebooks/oeb/transforms/rasterize.py
+++ b/src/calibre/ebooks/oeb/transforms/rasterize.py
@@ -11,14 +11,10 @@ from base64 import standard_b64encode
 from functools import lru_cache
 
 from lxml import etree
-from qt.core import (
-    QBuffer, QByteArray, QColor, QImage, QIODevice, QPainter, QSvgRenderer, Qt,
-)
+from qt.core import QBuffer, QByteArray, QColor, QImage, QIODevice, QPainter, QSvgRenderer, Qt
 
 from calibre import guess_type
-from calibre.ebooks.oeb.base import (
-    PNG_MIME, SVG_MIME, XHTML, XLINK, urlnormalize, xml2str, xpath,
-)
+from calibre.ebooks.oeb.base import PNG_MIME, SVG_MIME, XHTML, XLINK, urlnormalize, xml2str, xpath
 from calibre.ebooks.oeb.stylizer import Stylizer
 from calibre.utils.imghdr import what
 from polyglot.urllib import urldefrag
diff --git a/src/calibre/ebooks/oeb/transforms/rescale.py b/src/calibre/ebooks/oeb/transforms/rescale.py
index dc7bc12475..78c9614979 100644
--- a/src/calibre/ebooks/oeb/transforms/rescale.py
+++ b/src/calibre/ebooks/oeb/transforms/rescale.py
@@ -20,9 +20,10 @@ class RescaleImages:
         self.rescale(max_size)
 
     def rescale(self, max_size: str = 'profile'):
-        from PIL import Image
         from io import BytesIO
 
+        from PIL import Image
+
         is_image_collection = getattr(self.opts, 'is_image_collection', False)
 
         if is_image_collection:
diff --git a/src/calibre/ebooks/oeb/transforms/split.py b/src/calibre/ebooks/oeb/transforms/split.py
index b6b4ea55b4..9cc17766f1 100644
--- a/src/calibre/ebooks/oeb/transforms/split.py
+++ b/src/calibre/ebooks/oeb/transforms/split.py
@@ -8,20 +8,24 @@ forced at "likely" locations to conform to size limitations. This transform
 assumes a prior call to the flatcss transform.
 '''
 
-import os, functools, collections, re, copy
+import collections
+import copy
+import functools
+import os
+import re
 from collections import OrderedDict
 
-from lxml.etree import XPath as _XPath
+from css_selectors import Select, SelectorError
 from lxml import etree
+from lxml.etree import XPath as _XPath
 
 from calibre import as_unicode, force_unicode
 from calibre.ebooks.epub import rules
-from calibre.ebooks.oeb.base import (OEB_STYLES, XPNSMAP as NAMESPACES,
-        urldefrag, rewrite_links, XHTML, urlnormalize)
+from calibre.ebooks.oeb.base import OEB_STYLES, XHTML, rewrite_links, urldefrag, urlnormalize
+from calibre.ebooks.oeb.base import XPNSMAP as NAMESPACES
 from calibre.ebooks.oeb.polish.split import do_split
 from polyglot.builtins import iteritems
 from polyglot.urllib import unquote
-from css_selectors import Select, SelectorError
 
 XPath = functools.partial(_XPath, namespaces=NAMESPACES)
 
diff --git a/src/calibre/ebooks/oeb/transforms/structure.py b/src/calibre/ebooks/oeb/transforms/structure.py
index 161bdc1a98..f715277ade 100644
--- a/src/calibre/ebooks/oeb/transforms/structure.py
+++ b/src/calibre/ebooks/oeb/transforms/structure.py
@@ -5,13 +5,14 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, uuid
+import re
+import uuid
+from collections import Counter, OrderedDict
 
 from lxml import etree
-from collections import OrderedDict, Counter
 
-from calibre.ebooks.oeb.base import XPNSMAP, TOC, XHTML, xml2text, barename
 from calibre.ebooks import ConversionError
+from calibre.ebooks.oeb.base import TOC, XHTML, XPNSMAP, barename, xml2text
 from polyglot.builtins import itervalues
 from polyglot.urllib import urlparse
 
diff --git a/src/calibre/ebooks/oeb/transforms/subset.py b/src/calibre/ebooks/oeb/transforms/subset.py
index a10b1d901d..a3d9270a17 100644
--- a/src/calibre/ebooks/oeb/transforms/subset.py
+++ b/src/calibre/ebooks/oeb/transforms/subset.py
@@ -9,10 +9,11 @@ import os
 from collections import defaultdict
 from io import BytesIO
 
+from tinycss.fonts3 import parse_font_family
+
 from calibre.ebooks.oeb.base import css_text, urlnormalize
 from calibre.utils.fonts.subset import subset
 from polyglot.builtins import iteritems
-from tinycss.fonts3 import parse_font_family
 
 
 def get_font_properties(rule, default=None):
diff --git a/src/calibre/ebooks/oeb/transforms/trimmanifest.py b/src/calibre/ebooks/oeb/transforms/trimmanifest.py
index fa09aae808..1886f245ab 100644
--- a/src/calibre/ebooks/oeb/transforms/trimmanifest.py
+++ b/src/calibre/ebooks/oeb/transforms/trimmanifest.py
@@ -6,8 +6,7 @@ OPF manifest trimming transform.
 __license__   = 'GPL v3'
 __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
-from calibre.ebooks.oeb.base import CSS_MIME, OEB_DOCS
-from calibre.ebooks.oeb.base import urlnormalize, iterlinks
+from calibre.ebooks.oeb.base import CSS_MIME, OEB_DOCS, iterlinks, urlnormalize
 from polyglot.urllib import urldefrag
 
 
diff --git a/src/calibre/ebooks/oeb/writer.py b/src/calibre/ebooks/oeb/writer.py
index 3d293d6efd..b30138101b 100644
--- a/src/calibre/ebooks/oeb/writer.py
+++ b/src/calibre/ebooks/oeb/writer.py
@@ -7,8 +7,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
 import os
-from calibre.ebooks.oeb.base import OPF_MIME, xml2str
-from calibre.ebooks.oeb.base import DirContainer, OEBError
+
+from calibre.ebooks.oeb.base import OPF_MIME, DirContainer, OEBError, xml2str
 
 __all__ = ['OEBWriter']
 
diff --git a/src/calibre/ebooks/pdb/__init__.py b/src/calibre/ebooks/pdb/__init__.py
index 12d74a04a8..ee8835f4de 100644
--- a/src/calibre/ebooks/pdb/__init__.py
+++ b/src/calibre/ebooks/pdb/__init__.py
@@ -13,11 +13,11 @@ FORMAT_READERS = None
 def _import_readers():
     global FORMAT_READERS
     from calibre.ebooks.pdb.ereader.reader import Reader as ereader_reader
+    from calibre.ebooks.pdb.haodoo.reader import Reader as haodoo_reader
     from calibre.ebooks.pdb.palmdoc.reader import Reader as palmdoc_reader
-    from calibre.ebooks.pdb.ztxt.reader import Reader as ztxt_reader
     from calibre.ebooks.pdb.pdf.reader import Reader as pdf_reader
     from calibre.ebooks.pdb.plucker.reader import Reader as plucker_reader
-    from calibre.ebooks.pdb.haodoo.reader import Reader as haodoo_reader
+    from calibre.ebooks.pdb.ztxt.reader import Reader as ztxt_reader
 
     FORMAT_READERS = {
         'PNPdPPrs': ereader_reader,
@@ -37,9 +37,9 @@ FORMAT_WRITERS = None
 
 def _import_writers():
     global FORMAT_WRITERS
+    from calibre.ebooks.pdb.ereader.writer import Writer as ereader_writer
     from calibre.ebooks.pdb.palmdoc.writer import Writer as palmdoc_writer
     from calibre.ebooks.pdb.ztxt.writer import Writer as ztxt_writer
-    from calibre.ebooks.pdb.ereader.writer import Writer as ereader_writer
 
     FORMAT_WRITERS = {
         'doc': palmdoc_writer,
diff --git a/src/calibre/ebooks/pdb/ereader/reader.py b/src/calibre/ebooks/pdb/ereader/reader.py
index fd547e6c2b..3edd14750f 100644
--- a/src/calibre/ebooks/pdb/ereader/reader.py
+++ b/src/calibre/ebooks/pdb/ereader/reader.py
@@ -7,9 +7,9 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from calibre.ebooks.pdb.ereader import EreaderError
-from calibre.ebooks.pdb.formatreader import FormatReader
 from calibre.ebooks.pdb.ereader.reader132 import Reader132
 from calibre.ebooks.pdb.ereader.reader202 import Reader202
+from calibre.ebooks.pdb.formatreader import FormatReader
 
 
 class Reader(FormatReader):
diff --git a/src/calibre/ebooks/pdb/ereader/reader132.py b/src/calibre/ebooks/pdb/ereader/reader132.py
index 16c35b8345..f479862ad5 100644
--- a/src/calibre/ebooks/pdb/ereader/reader132.py
+++ b/src/calibre/ebooks/pdb/ereader/reader132.py
@@ -102,8 +102,7 @@ class Reader132(FormatReader):
         return self.decompress_text(number)
 
     def extract_content(self, output_dir):
-        from calibre.ebooks.pml.pmlconverter import footnote_to_html, sidebar_to_html
-        from calibre.ebooks.pml.pmlconverter import PML_HTMLizer
+        from calibre.ebooks.pml.pmlconverter import PML_HTMLizer, footnote_to_html, sidebar_to_html
 
         output_dir = os.path.abspath(output_dir)
 
diff --git a/src/calibre/ebooks/pdb/haodoo/reader.py b/src/calibre/ebooks/pdb/haodoo/reader.py
index d308cb98ef..945efa7cdd 100644
--- a/src/calibre/ebooks/pdb/haodoo/reader.py
+++ b/src/calibre/ebooks/pdb/haodoo/reader.py
@@ -7,13 +7,13 @@ __copyright__ = '2012, Kan-Ru Chen <kanru@kanru.info>'
 __docformat__ = 'restructuredtext en'
 
 
-import struct
 import os
+import struct
 
 from calibre import prepare_string_for_xml
-from calibre.ebooks.pdb.formatreader import FormatReader
 from calibre.ebooks.metadata import MetaInformation
-from calibre.ebooks.txt.processor import opf_writer, HTML_TEMPLATE
+from calibre.ebooks.pdb.formatreader import FormatReader
+from calibre.ebooks.txt.processor import HTML_TEMPLATE, opf_writer
 
 BPDB_IDENT = 'BOOKMTIT'
 UPDB_IDENT = 'BOOKMTIU'
diff --git a/src/calibre/ebooks/pdb/header.py b/src/calibre/ebooks/pdb/header.py
index b4acdf0e5a..4c990abeae 100644
--- a/src/calibre/ebooks/pdb/header.py
+++ b/src/calibre/ebooks/pdb/header.py
@@ -9,6 +9,7 @@ __docformat__ = 'restructuredtext en'
 import re
 import struct
 import time
+
 from polyglot.builtins import long_type
 
 
diff --git a/src/calibre/ebooks/pdb/palmdoc/reader.py b/src/calibre/ebooks/pdb/palmdoc/reader.py
index 4dd0a2a113..463e5d0115 100644
--- a/src/calibre/ebooks/pdb/palmdoc/reader.py
+++ b/src/calibre/ebooks/pdb/palmdoc/reader.py
@@ -6,8 +6,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-import struct, io
-
+import io
+import struct
 
 from calibre.ebooks.pdb.formatreader import FormatReader
 
diff --git a/src/calibre/ebooks/pdb/palmdoc/writer.py b/src/calibre/ebooks/pdb/palmdoc/writer.py
index 43de51e008..b2f659d6d7 100644
--- a/src/calibre/ebooks/pdb/palmdoc/writer.py
+++ b/src/calibre/ebooks/pdb/palmdoc/writer.py
@@ -10,8 +10,8 @@ import struct
 
 from calibre.ebooks.pdb.formatwriter import FormatWriter
 from calibre.ebooks.pdb.header import PdbHeaderBuilder
-from calibre.ebooks.txt.txtml import TXTMLizer
 from calibre.ebooks.txt.newlines import TxtNewlines, specified_newlines
+from calibre.ebooks.txt.txtml import TXTMLizer
 
 MAX_RECORD_SIZE = 4096
 
diff --git a/src/calibre/ebooks/pdb/plucker/reader.py b/src/calibre/ebooks/pdb/plucker/reader.py
index 4a9ac3313e..9df38f9e8f 100644
--- a/src/calibre/ebooks/pdb/plucker/reader.py
+++ b/src/calibre/ebooks/pdb/plucker/reader.py
@@ -5,14 +5,13 @@ __docformat__ = 'restructuredtext en'
 import os
 import struct
 import zlib
-
 from collections import OrderedDict
 
 from calibre import CurrentDir
-from calibre.ebooks.pdb.formatreader import FormatReader
 from calibre.ebooks.compression.palmdoc import decompress_doc
+from calibre.ebooks.pdb.formatreader import FormatReader
+from calibre.utils.img import Canvas, image_from_data, save_cover_data_to
 from calibre.utils.imghdr import identify
-from calibre.utils.img import save_cover_data_to, Canvas, image_from_data
 from polyglot.builtins import codepoint_to_chr
 
 DATATYPE_PHTML = 0
diff --git a/src/calibre/ebooks/pdb/ztxt/reader.py b/src/calibre/ebooks/pdb/ztxt/reader.py
index ef0ebebc2b..56678193e7 100644
--- a/src/calibre/ebooks/pdb/ztxt/reader.py
+++ b/src/calibre/ebooks/pdb/ztxt/reader.py
@@ -6,10 +6,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
+import io
 import struct
 import zlib
-import io
-
 
 from calibre.ebooks.pdb.formatreader import FormatReader
 from calibre.ebooks.pdb.ztxt import zTXTError
diff --git a/src/calibre/ebooks/pdb/ztxt/writer.py b/src/calibre/ebooks/pdb/ztxt/writer.py
index 4a75c471d8..01ce97c517 100644
--- a/src/calibre/ebooks/pdb/ztxt/writer.py
+++ b/src/calibre/ebooks/pdb/ztxt/writer.py
@@ -6,12 +6,13 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-import struct, zlib
+import struct
+import zlib
 
 from calibre.ebooks.pdb.formatwriter import FormatWriter
 from calibre.ebooks.pdb.header import PdbHeaderBuilder
-from calibre.ebooks.txt.txtml import TXTMLizer
 from calibre.ebooks.txt.newlines import TxtNewlines, specified_newlines
+from calibre.ebooks.txt.txtml import TXTMLizer
 
 MAX_RECORD_SIZE = 8192
 
diff --git a/src/calibre/ebooks/pdf/develop.py b/src/calibre/ebooks/pdf/develop.py
index 9732fd9d8c..27591cb22d 100644
--- a/src/calibre/ebooks/pdf/develop.py
+++ b/src/calibre/ebooks/pdf/develop.py
@@ -4,7 +4,7 @@
 
 import sys
 
-from qt.core import QApplication, QUrl, QPageLayout, QPageSize, QMarginsF
+from qt.core import QApplication, QMarginsF, QPageLayout, QPageSize, QUrl
 from qt.webengine import QWebEnginePage
 
 from calibre.gui2 import load_builtin_fonts, must_use_qt
diff --git a/src/calibre/ebooks/pdf/html_writer.py b/src/calibre/ebooks/pdf/html_writer.py
index 98ef90e344..ecfbcb78fc 100644
--- a/src/calibre/ebooks/pdf/html_writer.py
+++ b/src/calibre/ebooks/pdf/html_writer.py
@@ -9,20 +9,21 @@ import signal
 import sys
 from collections import namedtuple
 from functools import lru_cache
-from html5_parser import parse
 from itertools import count, repeat
-from qt.core import (
-    QApplication, QByteArray, QMarginsF, QObject, QPageLayout, Qt, QTimer, QUrl,
-    pyqtSignal, sip,
-)
+
+from html5_parser import parse
+from qt.core import QApplication, QByteArray, QMarginsF, QObject, QPageLayout, Qt, QTimer, QUrl, pyqtSignal, sip
 from qt.webengine import (
-    QWebEnginePage, QWebEngineProfile, QWebEngineSettings,
-    QWebEngineUrlRequestInterceptor, QWebEngineUrlRequestJob,
+    QWebEnginePage,
+    QWebEngineProfile,
+    QWebEngineSettings,
+    QWebEngineUrlRequestInterceptor,
+    QWebEngineUrlRequestJob,
     QWebEngineUrlSchemeHandler,
 )
 
 from calibre import detect_ncpus, human_readable, prepare_string_for_xml
-from calibre.constants import FAKE_HOST, FAKE_PROTOCOL, __version__, ismacos, iswindows, __appname__
+from calibre.constants import FAKE_HOST, FAKE_PROTOCOL, __appname__, __version__, ismacos, iswindows
 from calibre.ebooks.metadata.xmp import metadata_to_xmp_packet
 from calibre.ebooks.oeb.base import XHTML, XPath
 from calibre.ebooks.oeb.polish.container import Container as ContainerBase
@@ -37,10 +38,7 @@ from calibre.utils.fonts.sfnt.merge import merge_truetype_fonts_for_pdf
 from calibre.utils.fonts.sfnt.subset import pdf_subset
 from calibre.utils.logging import default_log
 from calibre.utils.monotonic import monotonic
-from calibre.utils.podofo import (
-    add_image_page, dedup_type3_fonts, get_podofo, remove_unused_fonts,
-    set_metadata_implementation,
-)
+from calibre.utils.podofo import add_image_page, dedup_type3_fonts, get_podofo, remove_unused_fonts, set_metadata_implementation
 from calibre.utils.resources import get_path as P
 from calibre.utils.short_uuid import uuid4
 from calibre.utils.webengine import secure_webengine, send_reply, setup_profile
diff --git a/src/calibre/ebooks/pdf/pdftohtml.py b/src/calibre/ebooks/pdf/pdftohtml.py
index 40eac81a63..1b6f2b0b74 100644
--- a/src/calibre/ebooks/pdf/pdftohtml.py
+++ b/src/calibre/ebooks/pdf/pdftohtml.py
@@ -122,6 +122,7 @@ def pdftohtml(output_dir, pdf_path, no_images, as_xml=False):
 
 def parse_outline(raw, output_dir):
     from lxml import etree
+
     from calibre.utils.xml_parse import safe_xml_fromstring
     raw = clean_xml_chars(xml_to_unicode(raw, strip_encoding_pats=True, assume_utf8=True)[0])
     outline = safe_xml_fromstring(raw).xpath('(//outline)[1]')
diff --git a/src/calibre/ebooks/pdf/reflow.py b/src/calibre/ebooks/pdf/reflow.py
index 4169f63c95..f66dd4dc00 100644
--- a/src/calibre/ebooks/pdf/reflow.py
+++ b/src/calibre/ebooks/pdf/reflow.py
@@ -5,7 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, numbers
+import numbers
+import os
+import sys
 from itertools import count
 
 from lxml import etree
diff --git a/src/calibre/ebooks/pdf/render/common.py b/src/calibre/ebooks/pdf/render/common.py
index 6c64fdd5c2..ff5e18d5f1 100644
--- a/src/calibre/ebooks/pdf/render/common.py
+++ b/src/calibre/ebooks/pdf/render/common.py
@@ -5,14 +5,16 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import codecs, zlib, numbers
-from io import BytesIO
+import codecs
+import numbers
+import zlib
 from datetime import datetime
+from io import BytesIO
 
 from calibre.utils.logging import default_log
-from polyglot.builtins import iteritems, codepoint_to_chr
-from polyglot.binary import as_hex_bytes
 from calibre_extensions.speedup import pdf_float
+from polyglot.binary import as_hex_bytes
+from polyglot.builtins import codepoint_to_chr, iteritems
 
 EOL = b'\n'
 
diff --git a/src/calibre/ebooks/pdf/render/fonts.py b/src/calibre/ebooks/pdf/render/fonts.py
index 6f59ac9ee0..b7a8fc510f 100644
--- a/src/calibre/ebooks/pdf/render/fonts.py
+++ b/src/calibre/ebooks/pdf/render/fonts.py
@@ -6,16 +6,15 @@ __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import re
+from collections import Counter, OrderedDict
 from itertools import groupby
 from operator import itemgetter
-from collections import Counter, OrderedDict
-from polyglot.builtins import iteritems, codepoint_to_chr
 
 from calibre import as_unicode
-from calibre.ebooks.pdf.render.common import (Array, String, Stream,
-    Dictionary, Name)
-from calibre.utils.fonts.sfnt.subset import pdf_subset, UnsupportedFont, NoGlyphs
+from calibre.ebooks.pdf.render.common import Array, Dictionary, Name, Stream, String
+from calibre.utils.fonts.sfnt.subset import NoGlyphs, UnsupportedFont, pdf_subset
 from calibre.utils.short_uuid import uuid4
+from polyglot.builtins import codepoint_to_chr, iteritems
 
 STANDARD_FONTS = {
     'Times-Roman', 'Helvetica', 'Courier', 'Symbol', 'Times-Bold',
diff --git a/src/calibre/ebooks/pdf/render/gradients.py b/src/calibre/ebooks/pdf/render/gradients.py
index 4880d25f16..6e9c1ae1fa 100644
--- a/src/calibre/ebooks/pdf/render/gradients.py
+++ b/src/calibre/ebooks/pdf/render/gradients.py
@@ -5,12 +5,13 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, copy
+import copy
+import sys
 from collections import namedtuple
 
 from qt.core import QLinearGradient, QPointF, sip
 
-from calibre.ebooks.pdf.render.common import Name, Array, Dictionary
+from calibre.ebooks.pdf.render.common import Array, Dictionary, Name
 
 Stop = namedtuple('Stop', 't color')
 
diff --git a/src/calibre/ebooks/pdf/render/graphics.py b/src/calibre/ebooks/pdf/render/graphics.py
index 2d28f9a830..70b43a6224 100644
--- a/src/calibre/ebooks/pdf/render/graphics.py
+++ b/src/calibre/ebooks/pdf/render/graphics.py
@@ -5,16 +5,14 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from math import sqrt
 from collections import namedtuple
+from math import sqrt
 
-from qt.core import (
-    QBrush, QPen, Qt, QPointF, QTransform, QPaintEngine, QImage)
+from qt.core import QBrush, QImage, QPaintEngine, QPen, QPointF, Qt, QTransform
 
-from calibre.ebooks.pdf.render.common import (
-    Name, Array, fmtnum, Stream, Dictionary)
-from calibre.ebooks.pdf.render.serialize import Path
+from calibre.ebooks.pdf.render.common import Array, Dictionary, Name, Stream, fmtnum
 from calibre.ebooks.pdf.render.gradients import LinearGradientPattern
+from calibre.ebooks.pdf.render.serialize import Path
 
 
 def convert_path(path):  # {{{
diff --git a/src/calibre/ebooks/pdf/render/links.py b/src/calibre/ebooks/pdf/render/links.py
index 7425fbbf47..2cdb491cdd 100644
--- a/src/calibre/ebooks/pdf/render/links.py
+++ b/src/calibre/ebooks/pdf/render/links.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.ebooks.pdf.render.common import Array, Name, Dictionary, String, UTF16String, current_log
+from calibre.ebooks.pdf.render.common import Array, Dictionary, Name, String, UTF16String, current_log
 from polyglot.builtins import iteritems
 from polyglot.urllib import unquote, urlparse
 
diff --git a/src/calibre/ebooks/pdf/render/serialize.py b/src/calibre/ebooks/pdf/render/serialize.py
index ceab4d97c9..0efe50e4ea 100644
--- a/src/calibre/ebooks/pdf/render/serialize.py
+++ b/src/calibre/ebooks/pdf/render/serialize.py
@@ -5,19 +5,17 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import hashlib, numbers
-from polyglot.builtins import iteritems
+import hashlib
+import numbers
 
-from qt.core import QBuffer, QByteArray, QImage, Qt, QColor, qRgba, QPainter
+from qt.core import QBuffer, QByteArray, QColor, QImage, QPainter, Qt, qRgba
 
-from calibre.constants import (__appname__, __version__)
-from calibre.ebooks.pdf.render.common import (
-    Reference, EOL, serialize, Stream, Dictionary, String, Name, Array,
-    fmtnum)
+from calibre.constants import __appname__, __version__
+from calibre.ebooks.pdf.render.common import EOL, Array, Dictionary, Name, Reference, Stream, String, fmtnum, serialize
 from calibre.ebooks.pdf.render.fonts import FontManager
 from calibre.ebooks.pdf.render.links import Links
 from calibre.utils.date import utcnow
-from polyglot.builtins import as_unicode
+from polyglot.builtins import as_unicode, iteritems
 
 PDFVER = b'%PDF-1.4'  # 1.4 is needed for XMP metadata
 
diff --git a/src/calibre/ebooks/pml/pmlconverter.py b/src/calibre/ebooks/pml/pmlconverter.py
index 0e361258ba..b9a04b9356 100644
--- a/src/calibre/ebooks/pml/pmlconverter.py
+++ b/src/calibre/ebooks/pml/pmlconverter.py
@@ -6,9 +6,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
+import io
 import os
 import re
-import io
 from copy import deepcopy
 
 from calibre import my_unichr, prepare_string_for_xml
diff --git a/src/calibre/ebooks/pml/pmlml.py b/src/calibre/ebooks/pml/pmlml.py
index b85c67cae9..f963956285 100644
--- a/src/calibre/ebooks/pml/pmlml.py
+++ b/src/calibre/ebooks/pml/pmlml.py
@@ -11,8 +11,8 @@ import re
 from lxml import etree
 
 from calibre.ebooks.pdb.ereader import image_name
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.ebooks.pml import unipmlcode
+from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.builtins import string_or_bytes
 
 TAG_MAP = {
@@ -110,8 +110,8 @@ class PMLMLizer:
         return output
 
     def get_cover_page(self):
-        from calibre.ebooks.oeb.stylizer import Stylizer
         from calibre.ebooks.oeb.base import XHTML
+        from calibre.ebooks.oeb.stylizer import Stylizer
 
         output = ''
         if 'cover' in self.oeb_book.guide:
@@ -128,8 +128,8 @@ class PMLMLizer:
         return output
 
     def get_text(self):
-        from calibre.ebooks.oeb.stylizer import Stylizer
         from calibre.ebooks.oeb.base import XHTML
+        from calibre.ebooks.oeb.stylizer import Stylizer
 
         text = ['']
         for item in self.oeb_book.spine:
diff --git a/src/calibre/ebooks/rb/__init__.py b/src/calibre/ebooks/rb/__init__.py
index 04f2e2045b..f7169e9583 100644
--- a/src/calibre/ebooks/rb/__init__.py
+++ b/src/calibre/ebooks/rb/__init__.py
@@ -4,7 +4,6 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-
 HEADER = b'\xb0\x0c\xb0\x0c\x02\x00NUVO\x00\x00\x00\x00'
 
 
diff --git a/src/calibre/ebooks/rb/rbml.py b/src/calibre/ebooks/rb/rbml.py
index 557dccc82d..908982269d 100644
--- a/src/calibre/ebooks/rb/rbml.py
+++ b/src/calibre/ebooks/rb/rbml.py
@@ -78,8 +78,8 @@ class RBMLizer:
         return output
 
     def get_cover_page(self):
-        from calibre.ebooks.oeb.stylizer import Stylizer
         from calibre.ebooks.oeb.base import XHTML
+        from calibre.ebooks.oeb.stylizer import Stylizer
         output = ''
         if 'cover' in self.oeb_book.guide:
             if self.name_map.get(self.oeb_book.guide['cover'].href, None):
@@ -108,8 +108,8 @@ class RBMLizer:
         return ''.join(toc)
 
     def get_text(self):
-        from calibre.ebooks.oeb.stylizer import Stylizer
         from calibre.ebooks.oeb.base import XHTML
+        from calibre.ebooks.oeb.stylizer import Stylizer
 
         output = ['']
         for item in self.oeb_book.spine:
diff --git a/src/calibre/ebooks/rb/reader.py b/src/calibre/ebooks/rb/reader.py
index 58a5ecb5bb..271686fb26 100644
--- a/src/calibre/ebooks/rb/reader.py
+++ b/src/calibre/ebooks/rb/reader.py
@@ -7,10 +7,9 @@ import struct
 import zlib
 
 from calibre import CurrentDir
-from calibre.ebooks.rb import HEADER
-from calibre.ebooks.rb import RocketBookError
-from calibre.ebooks.metadata.rb import get_metadata
 from calibre.ebooks.metadata.opf2 import OPFCreator
+from calibre.ebooks.metadata.rb import get_metadata
+from calibre.ebooks.rb import HEADER, RocketBookError
 from polyglot.builtins import as_unicode
 from polyglot.urllib import unquote
 
diff --git a/src/calibre/ebooks/rb/writer.py b/src/calibre/ebooks/rb/writer.py
index 195339e3da..5c2bf7396a 100644
--- a/src/calibre/ebooks/rb/writer.py
+++ b/src/calibre/ebooks/rb/writer.py
@@ -8,10 +8,9 @@ import zlib
 
 from PIL import Image
 
-from calibre.ebooks.rb.rbml import RBMLizer
-from calibre.ebooks.rb import HEADER
-from calibre.ebooks.rb import unique_name
 from calibre.constants import __appname__, __version__
+from calibre.ebooks.rb import HEADER, unique_name
+from calibre.ebooks.rb.rbml import RBMLizer
 
 TEXT_RECORD_SIZE = 4096
 
diff --git a/src/calibre/ebooks/readability/cleaners.py b/src/calibre/ebooks/readability/cleaners.py
index 1f67810c89..fee5aec96f 100644
--- a/src/calibre/ebooks/readability/cleaners.py
+++ b/src/calibre/ebooks/readability/cleaners.py
@@ -1,5 +1,6 @@
 # strip out a set of nuisance html attributes that can mess up rendering in RSS feeds
 import re
+
 from lxml.html.clean import Cleaner
 
 bad_attrs = ['width', 'height', 'style', '[-a-z]*color', 'background[-a-z]*', 'on*']
diff --git a/src/calibre/ebooks/readability/htmls.py b/src/calibre/ebooks/readability/htmls.py
index 9c9289face..c4b104a5b6 100644
--- a/src/calibre/ebooks/readability/htmls.py
+++ b/src/calibre/ebooks/readability/htmls.py
@@ -1,10 +1,10 @@
 import re
 
-from lxml.html import tostring
 import lxml.html
+from lxml.html import tostring
 
-from calibre.ebooks.readability.cleaners import normalize_spaces, clean_attributes
 from calibre.ebooks.chardet import xml_to_unicode
+from calibre.ebooks.readability.cleaners import clean_attributes, normalize_spaces
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/ebooks/readability/readability.py b/src/calibre/ebooks/readability/readability.py
index edffc0c4ff..bed0759a79 100644
--- a/src/calibre/ebooks/readability/readability.py
+++ b/src/calibre/ebooks/readability/readability.py
@@ -1,16 +1,16 @@
 #!/usr/bin/env python
 
 
-import re, sys
+import re
+import sys
 from collections import defaultdict
 
-from polyglot.builtins import reraise
-
-from lxml.html import (fragment_fromstring, document_fromstring,
-        tostring as htostring)
+from lxml.html import document_fromstring, fragment_fromstring
+from lxml.html import tostring as htostring
 
+from calibre.ebooks.readability.cleaners import clean_attributes, html_cleaner
 from calibre.ebooks.readability.htmls import build_doc, get_body, get_title, shorten_title
-from calibre.ebooks.readability.cleaners import html_cleaner, clean_attributes
+from polyglot.builtins import reraise
 
 
 def tounicode(tree_or_node, **kwargs):
diff --git a/src/calibre/ebooks/render_html.py b/src/calibre/ebooks/render_html.py
index 285adc9a32..e4100e607b 100644
--- a/src/calibre/ebooks/render_html.py
+++ b/src/calibre/ebooks/render_html.py
@@ -4,13 +4,15 @@
 
 import os
 import sys
-from qt.core import (
-    QApplication, QByteArray, QMarginsF, QPageLayout, QPageSize, Qt, QTimer, QUrl
-)
+
+from qt.core import QApplication, QByteArray, QMarginsF, QPageLayout, QPageSize, Qt, QTimer, QUrl
 from qt.webengine import (
-    QWebEnginePage, QWebEngineProfile, QWebEngineScript,
-    QWebEngineUrlRequestInterceptor, QWebEngineUrlRequestJob,
-    QWebEngineUrlSchemeHandler
+    QWebEnginePage,
+    QWebEngineProfile,
+    QWebEngineScript,
+    QWebEngineUrlRequestInterceptor,
+    QWebEngineUrlRequestJob,
+    QWebEngineUrlSchemeHandler,
 )
 
 from calibre.constants import FAKE_HOST, FAKE_PROTOCOL
@@ -21,9 +23,7 @@ from calibre.gui_launch import setup_qt_logging
 from calibre.utils.filenames import atomic_rename
 from calibre.utils.logging import default_log
 from calibre.utils.monotonic import monotonic
-from calibre.utils.webengine import (
-    secure_webengine, send_reply, setup_fake_protocol, setup_profile
-)
+from calibre.utils.webengine import secure_webengine, send_reply, setup_fake_protocol, setup_profile
 
 LOAD_TIMEOUT = 20
 PRINT_TIMEOUT = 10
@@ -148,9 +148,7 @@ class Render(QWebEnginePage):
                     if type(getattr(QPageSize, sz, None)) is type(QPageSize.PageSizeId.A4):  # noqa
                         page_size = QPageSize(getattr(QPageSize, sz))
                     else:
-                        from calibre.ebooks.pdf.image_writer import (
-                            parse_pdf_page_size
-                        )
+                        from calibre.ebooks.pdf.image_writer import parse_pdf_page_size
                         ps = parse_pdf_page_size(sz, data.get('unit', 'inch'))
                         if ps is not None:
                             page_size = ps
diff --git a/src/calibre/ebooks/rtf/rtfml.py b/src/calibre/ebooks/rtf/rtfml.py
index 7dd24b199c..52ac036f12 100644
--- a/src/calibre/ebooks/rtf/rtfml.py
+++ b/src/calibre/ebooks/rtf/rtfml.py
@@ -6,9 +6,9 @@ __docformat__ = 'restructuredtext en'
 Transform OEB content into RTF markup
 '''
 
+import io
 import os
 import re
-import io
 from binascii import hexlify
 
 from lxml import etree
@@ -212,8 +212,7 @@ class RTFMLizer:
         return text
 
     def dump_text(self, elem, stylizer, tag_stack=[]):
-        from calibre.ebooks.oeb.base import (XHTML_NS, namespace, barename,
-                urlnormalize)
+        from calibre.ebooks.oeb.base import XHTML_NS, barename, namespace, urlnormalize
 
         if not isinstance(elem.tag, string_or_bytes) \
            or namespace(elem.tag) != XHTML_NS:
diff --git a/src/calibre/ebooks/rtf2xml/ParseRtf.py b/src/calibre/ebooks/rtf2xml/ParseRtf.py
index 13c7510daa..4c182370b9 100644
--- a/src/calibre/ebooks/rtf2xml/ParseRtf.py
+++ b/src/calibre/ebooks/rtf2xml/ParseRtf.py
@@ -12,18 +12,47 @@
 #########################################################################
 # $Revision: 1.41 $
 # $Date: 2006/03/24 23:50:07 $
-import sys, os
+import os
+import sys
 
-from calibre.ebooks.rtf2xml import headings_to_sections, \
-    line_endings, footnote, fields_small, default_encoding, \
-    make_lists, preamble_div, header, colors, group_borders, \
-    check_encoding, add_brackets, table, combine_borders, \
-    fields_large, process_tokens, hex_2_utf8, tokenize, \
-    delete_info, sections, check_brackets, styles, \
-    paragraph_def, convert_to_tags, output, copy, \
-    list_numbers, info, pict, table_info, fonts, paragraphs, \
-    body_styles, preamble_rest, group_styles, \
-    inline
+from calibre.ebooks.rtf2xml import (
+    add_brackets,
+    body_styles,
+    check_brackets,
+    check_encoding,
+    colors,
+    combine_borders,
+    convert_to_tags,
+    copy,
+    default_encoding,
+    delete_info,
+    fields_large,
+    fields_small,
+    fonts,
+    footnote,
+    group_borders,
+    group_styles,
+    header,
+    headings_to_sections,
+    hex_2_utf8,
+    info,
+    inline,
+    line_endings,
+    list_numbers,
+    make_lists,
+    output,
+    paragraph_def,
+    paragraphs,
+    pict,
+    preamble_div,
+    preamble_rest,
+    process_tokens,
+    sections,
+    styles,
+    table,
+    table_info,
+    tokenize,
+)
 from calibre.ebooks.rtf2xml.old_rtf import OldRtf
 
 from . import open_for_read, open_for_write
diff --git a/src/calibre/ebooks/rtf2xml/add_brackets.py b/src/calibre/ebooks/rtf2xml/add_brackets.py
index e6533460e6..30b03d829c 100644
--- a/src/calibre/ebooks/rtf2xml/add_brackets.py
+++ b/src/calibre/ebooks/rtf2xml/add_brackets.py
@@ -11,11 +11,13 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
-from calibre.ebooks.rtf2xml import copy, check_brackets
+from calibre.ebooks.rtf2xml import check_brackets, copy
 from calibre.ptempfile import better_mktemp
 from polyglot.builtins import iteritems
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/body_styles.py b/src/calibre/ebooks/rtf2xml/body_styles.py
index 1876264971..65d784513a 100644
--- a/src/calibre/ebooks/rtf2xml/body_styles.py
+++ b/src/calibre/ebooks/rtf2xml/body_styles.py
@@ -11,8 +11,10 @@
 #                                                                       #
 #########################################################################
 import os
+
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 """
diff --git a/src/calibre/ebooks/rtf2xml/colors.py b/src/calibre/ebooks/rtf2xml/colors.py
index a8aab50230..7f0fa81c7b 100644
--- a/src/calibre/ebooks/rtf2xml/colors.py
+++ b/src/calibre/ebooks/rtf2xml/colors.py
@@ -10,10 +10,13 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os, re
+import os
+import re
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/combine_borders.py b/src/calibre/ebooks/rtf2xml/combine_borders.py
index 85262d8b89..f8ed8d0b05 100644
--- a/src/calibre/ebooks/rtf2xml/combine_borders.py
+++ b/src/calibre/ebooks/rtf2xml/combine_borders.py
@@ -14,6 +14,7 @@ import os
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/configure_txt.py b/src/calibre/ebooks/rtf2xml/configure_txt.py
index c66a1c961e..d0414f33a4 100644
--- a/src/calibre/ebooks/rtf2xml/configure_txt.py
+++ b/src/calibre/ebooks/rtf2xml/configure_txt.py
@@ -1,4 +1,6 @@
-import os, sys
+import os
+import sys
+
 from . import open_for_read
 
 
diff --git a/src/calibre/ebooks/rtf2xml/convert_to_tags.py b/src/calibre/ebooks/rtf2xml/convert_to_tags.py
index 4b470d442b..150036c081 100644
--- a/src/calibre/ebooks/rtf2xml/convert_to_tags.py
+++ b/src/calibre/ebooks/rtf2xml/convert_to_tags.py
@@ -1,7 +1,9 @@
-import os, sys
+import os
+import sys
 
-from calibre.ebooks.rtf2xml import copy, check_encoding
+from calibre.ebooks.rtf2xml import check_encoding, copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 public_dtd = 'rtf2xml1.0.dtd'
diff --git a/src/calibre/ebooks/rtf2xml/copy.py b/src/calibre/ebooks/rtf2xml/copy.py
index e89d24c002..7f2fab0898 100644
--- a/src/calibre/ebooks/rtf2xml/copy.py
+++ b/src/calibre/ebooks/rtf2xml/copy.py
@@ -10,7 +10,8 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import os, shutil
+import os
+import shutil
 
 
 class Copy:
diff --git a/src/calibre/ebooks/rtf2xml/default_encoding.py b/src/calibre/ebooks/rtf2xml/default_encoding.py
index 5d1461c57c..d6d411bde3 100644
--- a/src/calibre/ebooks/rtf2xml/default_encoding.py
+++ b/src/calibre/ebooks/rtf2xml/default_encoding.py
@@ -56,6 +56,7 @@ Codepages as to RTF 1.9.1:
     57011	Punjabi
 '''
 import re
+
 from . import open_for_read
 
 
diff --git a/src/calibre/ebooks/rtf2xml/delete_info.py b/src/calibre/ebooks/rtf2xml/delete_info.py
index b45e3d122d..f5743f50d2 100644
--- a/src/calibre/ebooks/rtf2xml/delete_info.py
+++ b/src/calibre/ebooks/rtf2xml/delete_info.py
@@ -10,10 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/field_strings.py b/src/calibre/ebooks/rtf2xml/field_strings.py
index 33602d46f7..257edcecb3 100644
--- a/src/calibre/ebooks/rtf2xml/field_strings.py
+++ b/src/calibre/ebooks/rtf2xml/field_strings.py
@@ -10,7 +10,8 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, re
+import re
+import sys
 
 
 class FieldStrings:
diff --git a/src/calibre/ebooks/rtf2xml/fields_large.py b/src/calibre/ebooks/rtf2xml/fields_large.py
index 2d4af119a9..5a208d2eae 100644
--- a/src/calibre/ebooks/rtf2xml/fields_large.py
+++ b/src/calibre/ebooks/rtf2xml/fields_large.py
@@ -10,9 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
-from calibre.ebooks.rtf2xml import field_strings, copy
+import os
+import sys
+
+from calibre.ebooks.rtf2xml import copy, field_strings
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/fields_small.py b/src/calibre/ebooks/rtf2xml/fields_small.py
index 3feef24eb8..d2a0fbd846 100644
--- a/src/calibre/ebooks/rtf2xml/fields_small.py
+++ b/src/calibre/ebooks/rtf2xml/fields_small.py
@@ -10,10 +10,13 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os, re
+import os
+import re
+import sys
 
-from calibre.ebooks.rtf2xml import field_strings, copy
+from calibre.ebooks.rtf2xml import copy, field_strings
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/fonts.py b/src/calibre/ebooks/rtf2xml/fonts.py
index 54ab352efa..a3fd4b9d53 100644
--- a/src/calibre/ebooks/rtf2xml/fonts.py
+++ b/src/calibre/ebooks/rtf2xml/fonts.py
@@ -10,10 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/get_options.py b/src/calibre/ebooks/rtf2xml/get_options.py
index 47aa3faf6a..5c5fd60b2f 100644
--- a/src/calibre/ebooks/rtf2xml/get_options.py
+++ b/src/calibre/ebooks/rtf2xml/get_options.py
@@ -13,8 +13,10 @@
 """
 Gets options for main part of script
 """
-import sys, os
-from calibre.ebooks.rtf2xml import options_trem, configure_txt
+import os
+import sys
+
+from calibre.ebooks.rtf2xml import configure_txt, options_trem
 
 
 class GetOptions:
diff --git a/src/calibre/ebooks/rtf2xml/group_borders.py b/src/calibre/ebooks/rtf2xml/group_borders.py
index 6fde25d7b2..3b6f118393 100644
--- a/src/calibre/ebooks/rtf2xml/group_borders.py
+++ b/src/calibre/ebooks/rtf2xml/group_borders.py
@@ -10,9 +10,13 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os, re
+import os
+import re
+import sys
+
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/group_styles.py b/src/calibre/ebooks/rtf2xml/group_styles.py
index f873650823..fa8bbaec44 100644
--- a/src/calibre/ebooks/rtf2xml/group_styles.py
+++ b/src/calibre/ebooks/rtf2xml/group_styles.py
@@ -10,9 +10,13 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os,  re
+import os
+import re
+import sys
+
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/header.py b/src/calibre/ebooks/rtf2xml/header.py
index 1d6e3261dd..85d8a384ed 100644
--- a/src/calibre/ebooks/rtf2xml/header.py
+++ b/src/calibre/ebooks/rtf2xml/header.py
@@ -10,10 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/headings_to_sections.py b/src/calibre/ebooks/rtf2xml/headings_to_sections.py
index b40f4cd9a5..6253f18f33 100644
--- a/src/calibre/ebooks/rtf2xml/headings_to_sections.py
+++ b/src/calibre/ebooks/rtf2xml/headings_to_sections.py
@@ -10,9 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import os, re
+import os
+import re
+
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/hex_2_utf8.py b/src/calibre/ebooks/rtf2xml/hex_2_utf8.py
index 48a45ce007..86905baeff 100644
--- a/src/calibre/ebooks/rtf2xml/hex_2_utf8.py
+++ b/src/calibre/ebooks/rtf2xml/hex_2_utf8.py
@@ -10,9 +10,11 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os, io
+import io
+import os
+import sys
 
-from calibre.ebooks.rtf2xml import get_char_map, copy
+from calibre.ebooks.rtf2xml import copy, get_char_map
 from calibre.ebooks.rtf2xml.char_set import char_set
 from calibre.ptempfile import better_mktemp
 
diff --git a/src/calibre/ebooks/rtf2xml/info.py b/src/calibre/ebooks/rtf2xml/info.py
index dbf619c79f..821b3ee68e 100644
--- a/src/calibre/ebooks/rtf2xml/info.py
+++ b/src/calibre/ebooks/rtf2xml/info.py
@@ -10,10 +10,13 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os, re
+import os
+import re
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/inline.py b/src/calibre/ebooks/rtf2xml/inline.py
index 4c103b454d..eadb8d2daf 100644
--- a/src/calibre/ebooks/rtf2xml/inline.py
+++ b/src/calibre/ebooks/rtf2xml/inline.py
@@ -1,7 +1,9 @@
-import sys, os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 """
diff --git a/src/calibre/ebooks/rtf2xml/line_endings.py b/src/calibre/ebooks/rtf2xml/line_endings.py
index 5dbc59a995..e34c4a98dc 100644
--- a/src/calibre/ebooks/rtf2xml/line_endings.py
+++ b/src/calibre/ebooks/rtf2xml/line_endings.py
@@ -13,8 +13,8 @@
 import os
 
 from calibre.ebooks.rtf2xml import copy
-from calibre.utils.cleantext import clean_ascii_chars
 from calibre.ptempfile import better_mktemp
+from calibre.utils.cleantext import clean_ascii_chars
 
 
 class FixLineEndings:
diff --git a/src/calibre/ebooks/rtf2xml/list_numbers.py b/src/calibre/ebooks/rtf2xml/list_numbers.py
index 6da6a34b8d..d9379087ad 100644
--- a/src/calibre/ebooks/rtf2xml/list_numbers.py
+++ b/src/calibre/ebooks/rtf2xml/list_numbers.py
@@ -11,8 +11,10 @@
 #                                                                       #
 #########################################################################
 import os
+
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/make_lists.py b/src/calibre/ebooks/rtf2xml/make_lists.py
index 137ad01e14..cd06075e47 100644
--- a/src/calibre/ebooks/rtf2xml/make_lists.py
+++ b/src/calibre/ebooks/rtf2xml/make_lists.py
@@ -10,7 +10,9 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os, re
+import os
+import re
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
diff --git a/src/calibre/ebooks/rtf2xml/output.py b/src/calibre/ebooks/rtf2xml/output.py
index 7a3b7d1167..f9f11b4f5c 100644
--- a/src/calibre/ebooks/rtf2xml/output.py
+++ b/src/calibre/ebooks/rtf2xml/output.py
@@ -10,8 +10,11 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
+
 from . import open_for_read, open_for_write
+
 # , codecs
 
 
diff --git a/src/calibre/ebooks/rtf2xml/paragraph_def.py b/src/calibre/ebooks/rtf2xml/paragraph_def.py
index acb2281a05..e5b63d7bf5 100644
--- a/src/calibre/ebooks/rtf2xml/paragraph_def.py
+++ b/src/calibre/ebooks/rtf2xml/paragraph_def.py
@@ -10,9 +10,10 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
-from calibre.ebooks.rtf2xml import copy, border_parse
+from calibre.ebooks.rtf2xml import border_parse, copy
 from calibre.ptempfile import better_mktemp
 
 from . import open_for_read, open_for_write
diff --git a/src/calibre/ebooks/rtf2xml/paragraphs.py b/src/calibre/ebooks/rtf2xml/paragraphs.py
index 425fd89312..a7786c4ea1 100644
--- a/src/calibre/ebooks/rtf2xml/paragraphs.py
+++ b/src/calibre/ebooks/rtf2xml/paragraphs.py
@@ -10,10 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/pict.py b/src/calibre/ebooks/rtf2xml/pict.py
index 0cd65c3067..46c8f23a06 100644
--- a/src/calibre/ebooks/rtf2xml/pict.py
+++ b/src/calibre/ebooks/rtf2xml/pict.py
@@ -10,7 +10,8 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
diff --git a/src/calibre/ebooks/rtf2xml/preamble_div.py b/src/calibre/ebooks/rtf2xml/preamble_div.py
index 760b170403..92c5ddb01f 100644
--- a/src/calibre/ebooks/rtf2xml/preamble_div.py
+++ b/src/calibre/ebooks/rtf2xml/preamble_div.py
@@ -10,9 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
-from calibre.ebooks.rtf2xml import copy, override_table, list_table
+import os
+import sys
+
+from calibre.ebooks.rtf2xml import copy, list_table, override_table
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/preamble_rest.py b/src/calibre/ebooks/rtf2xml/preamble_rest.py
index 7bc731a4e3..785325581d 100644
--- a/src/calibre/ebooks/rtf2xml/preamble_rest.py
+++ b/src/calibre/ebooks/rtf2xml/preamble_rest.py
@@ -10,9 +10,11 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys,os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/process_tokens.py b/src/calibre/ebooks/rtf2xml/process_tokens.py
index d773a12dc7..f118f0deef 100644
--- a/src/calibre/ebooks/rtf2xml/process_tokens.py
+++ b/src/calibre/ebooks/rtf2xml/process_tokens.py
@@ -10,9 +10,10 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import os, re
+import os
+import re
 
-from calibre.ebooks.rtf2xml import copy, check_brackets
+from calibre.ebooks.rtf2xml import check_brackets, copy
 from calibre.ptempfile import better_mktemp
 
 from . import open_for_read, open_for_write
@@ -719,7 +720,7 @@ class ProcessTokens:
         try:
             # calibre why ignore negative number? Wrong in case of \fi
             numerator = float(re.search('[0-9.\\-]+', numerator).group())
-        except TypeError as msg:
+        except TypeError:
             if self.__run_level > 3:
                 msg = ('No number to process?\nthis indicates that the token \\(\\li\\) \
                 should have a number and does not\nnumerator is \
diff --git a/src/calibre/ebooks/rtf2xml/replace_illegals.py b/src/calibre/ebooks/rtf2xml/replace_illegals.py
index 7b811fce95..c2521922e6 100644
--- a/src/calibre/ebooks/rtf2xml/replace_illegals.py
+++ b/src/calibre/ebooks/rtf2xml/replace_illegals.py
@@ -13,8 +13,9 @@
 import os
 
 from calibre.ebooks.rtf2xml import copy
-from calibre.utils.cleantext import clean_ascii_chars
 from calibre.ptempfile import better_mktemp
+from calibre.utils.cleantext import clean_ascii_chars
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/sections.py b/src/calibre/ebooks/rtf2xml/sections.py
index 2b8865c4ad..16c000f3be 100644
--- a/src/calibre/ebooks/rtf2xml/sections.py
+++ b/src/calibre/ebooks/rtf2xml/sections.py
@@ -10,7 +10,8 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
diff --git a/src/calibre/ebooks/rtf2xml/styles.py b/src/calibre/ebooks/rtf2xml/styles.py
index f717a1f907..99cdeff9f1 100644
--- a/src/calibre/ebooks/rtf2xml/styles.py
+++ b/src/calibre/ebooks/rtf2xml/styles.py
@@ -10,9 +10,12 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
-from calibre.ebooks.rtf2xml import copy, border_parse
+import os
+import sys
+
+from calibre.ebooks.rtf2xml import border_parse, copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/rtf2xml/table.py b/src/calibre/ebooks/rtf2xml/table.py
index 9fd65ca5df..68576424b1 100644
--- a/src/calibre/ebooks/rtf2xml/table.py
+++ b/src/calibre/ebooks/rtf2xml/table.py
@@ -10,9 +10,10 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import sys, os
+import os
+import sys
 
-from calibre.ebooks.rtf2xml import copy, border_parse
+from calibre.ebooks.rtf2xml import border_parse, copy
 from calibre.ptempfile import better_mktemp
 
 from . import open_for_read, open_for_write
diff --git a/src/calibre/ebooks/rtf2xml/table_info.py b/src/calibre/ebooks/rtf2xml/table_info.py
index 04a0bdc719..56983c2280 100644
--- a/src/calibre/ebooks/rtf2xml/table_info.py
+++ b/src/calibre/ebooks/rtf2xml/table_info.py
@@ -11,8 +11,10 @@
 #                                                                       #
 #########################################################################
 import os
+
 from calibre.ebooks.rtf2xml import copy
 from calibre.ptempfile import better_mktemp
+
 from . import open_for_read, open_for_write
 
 # note to self. This is the first module in which I use tempfile. A good idea?
diff --git a/src/calibre/ebooks/rtf2xml/tokenize.py b/src/calibre/ebooks/rtf2xml/tokenize.py
index fcd2fb3dd2..6a9bde8830 100644
--- a/src/calibre/ebooks/rtf2xml/tokenize.py
+++ b/src/calibre/ebooks/rtf2xml/tokenize.py
@@ -10,12 +10,14 @@
 #                                                                       #
 #                                                                       #
 #########################################################################
-import os, re
+import os
+import re
 
 from calibre.ebooks.rtf2xml import copy
-from calibre.utils.mreplace import MReplace
 from calibre.ptempfile import better_mktemp
+from calibre.utils.mreplace import MReplace
 from polyglot.builtins import codepoint_to_chr
+
 from . import open_for_read, open_for_write
 
 
diff --git a/src/calibre/ebooks/snb/snbfile.py b/src/calibre/ebooks/snb/snbfile.py
index 3f87046e29..07536bf880 100644
--- a/src/calibre/ebooks/snb/snbfile.py
+++ b/src/calibre/ebooks/snb/snbfile.py
@@ -2,7 +2,11 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Li Fanxi <lifanxi@freemindworld.com>'
 __docformat__ = 'restructuredtext en'
 
-import sys, struct, zlib, bz2, os
+import bz2
+import os
+import struct
+import sys
+import zlib
 
 from calibre import guess_type
 
diff --git a/src/calibre/ebooks/snb/snbml.py b/src/calibre/ebooks/snb/snbml.py
index f482f2a33e..4d09d20cb6 100644
--- a/src/calibre/ebooks/snb/snbml.py
+++ b/src/calibre/ebooks/snb/snbml.py
@@ -10,6 +10,7 @@ import os
 import re
 
 from lxml import etree
+
 from polyglot.builtins import string_or_bytes
 
 
diff --git a/src/calibre/ebooks/textile/__init__.py b/src/calibre/ebooks/textile/__init__.py
index 1acbfc38fc..c566ffac6d 100644
--- a/src/calibre/ebooks/textile/__init__.py
+++ b/src/calibre/ebooks/textile/__init__.py
@@ -1,4 +1,4 @@
-from .functions import textile, textile_restricted, Textile
+from .functions import Textile, textile, textile_restricted
 
 if False:
     textile, textile_restricted, Textile
diff --git a/src/calibre/ebooks/tweak.py b/src/calibre/ebooks/tweak.py
index b083b5cf2a..8f372c25e0 100644
--- a/src/calibre/ebooks/tweak.py
+++ b/src/calibre/ebooks/tweak.py
@@ -5,14 +5,16 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, unicodedata
+import os
+import sys
+import unicodedata
 
-from calibre import prints, as_unicode, walk
-from calibre.constants import iswindows, __appname__
-from calibre.ptempfile import TemporaryDirectory
+from calibre import as_unicode, prints, walk
+from calibre.constants import __appname__, iswindows
 from calibre.libunzip import extract as zipextract
-from calibre.utils.zipfile import ZipFile, ZIP_DEFLATED, ZIP_STORED
+from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.ipc.simple_worker import WorkerError
+from calibre.utils.zipfile import ZIP_DEFLATED, ZIP_STORED, ZipFile
 
 
 class Error(ValueError):
@@ -27,7 +29,8 @@ def ask_cli_question(msg):
         import msvcrt
         ans = msvcrt.getch()
     else:
-        import tty, termios
+        import termios
+        import tty
         old_settings = termios.tcgetattr(sys.stdin.fileno())
         try:
             tty.setraw(sys.stdin.fileno())
@@ -42,7 +45,7 @@ def ask_cli_question(msg):
 
 
 def mobi_exploder(path, tdir, question=lambda x:True):
-    from calibre.ebooks.mobi.tweak import explode, BadFormat
+    from calibre.ebooks.mobi.tweak import BadFormat, explode
     try:
         return explode(path, tdir, question=question)
     except BadFormat as e:
diff --git a/src/calibre/ebooks/txt/markdownml.py b/src/calibre/ebooks/txt/markdownml.py
index f09d920d13..aa9d1f5291 100644
--- a/src/calibre/ebooks/txt/markdownml.py
+++ b/src/calibre/ebooks/txt/markdownml.py
@@ -7,7 +7,6 @@ __docformat__ = 'restructuredtext en'
 Transform OEB content into Textile formatted plain text
 '''
 import re
-
 from functools import partial
 
 from calibre.ebooks.htmlz.oeb2html import OEB2HTML
diff --git a/src/calibre/ebooks/txt/processor.py b/src/calibre/ebooks/txt/processor.py
index 47206e44f9..45fc22eded 100644
--- a/src/calibre/ebooks/txt/processor.py
+++ b/src/calibre/ebooks/txt/processor.py
@@ -7,12 +7,12 @@ __docformat__ = 'restructuredtext en'
 Read content from txt file.
 '''
 
-import os, re
-
-from calibre import prepare_string_for_xml, isbytestring
-from calibre.ebooks.metadata.opf2 import OPFCreator
+import os
+import re
 
+from calibre import isbytestring, prepare_string_for_xml
 from calibre.ebooks.conversion.preprocess import DocAnalysis
+from calibre.ebooks.metadata.opf2 import OPFCreator
 from calibre.utils.cleantext import clean_ascii_chars
 from polyglot.builtins import iteritems
 
@@ -106,9 +106,11 @@ DEFAULT_MD_EXTENSIONS = ('footnotes', 'tables', 'toc')
 def create_markdown_object(extensions):
     # Need to load markdown extensions without relying on pkg_resources
     import importlib
-    from calibre.ebooks.markdown import Markdown
+
     from markdown import Extension
 
+    from calibre.ebooks.markdown import Markdown
+
     class NotBrainDeadMarkdown(Markdown):
         def build_extension(self, ext_name, configs):
             if '.' in ext_name or ':' in ext_name:
@@ -135,9 +137,9 @@ def convert_markdown(txt, title='', extensions=DEFAULT_MD_EXTENSIONS):
 
 
 def convert_markdown_with_metadata(txt, title='', extensions=DEFAULT_MD_EXTENSIONS):
+    from calibre.db.write import get_series_values
     from calibre.ebooks.metadata.book.base import Metadata
     from calibre.utils.date import parse_only_date
-    from calibre.db.write import get_series_values
     if 'meta' not in extensions:
         extensions.append('meta')
     md = create_markdown_object(extensions)
@@ -355,8 +357,8 @@ def detect_formatting_type(txt):
 
 
 def get_images_from_polyglot_text(txt: str, base_dir: str = '', file_ext: str = 'txt') -> set:
-    from calibre.ebooks.oeb.base import OEB_IMAGES
     from calibre import guess_type
+    from calibre.ebooks.oeb.base import OEB_IMAGES
     if not base_dir:
         base_dir = os.getcwd()
     images = set()
diff --git a/src/calibre/ebooks/txt/textileml.py b/src/calibre/ebooks/txt/textileml.py
index 8411714137..6d75b3a62e 100644
--- a/src/calibre/ebooks/txt/textileml.py
+++ b/src/calibre/ebooks/txt/textileml.py
@@ -6,13 +6,12 @@ __docformat__ = 'restructuredtext en'
 Transform OEB content into Textile formatted plain text
 '''
 import re
-
 from functools import partial
 
+from calibre.ebooks import unit_convert
 from calibre.ebooks.htmlz.oeb2html import OEB2HTML
 from calibre.ebooks.oeb.base import XHTML, XHTML_NS, barename, namespace, rewrite_links
 from calibre.ebooks.oeb.stylizer import Stylizer
-from calibre.ebooks import unit_convert
 from calibre.ebooks.textile.unsmarten import unsmarten
 from polyglot.builtins import string_or_bytes
 
diff --git a/src/calibre/ebooks/txt/txtml.py b/src/calibre/ebooks/txt/txtml.py
index b3ed04187f..4c5a39c72e 100644
--- a/src/calibre/ebooks/txt/txtml.py
+++ b/src/calibre/ebooks/txt/txtml.py
@@ -9,8 +9,8 @@ Transform OEB content into plain text
 import re
 
 from lxml import etree
-from polyglot.builtins import string_or_bytes
 
+from polyglot.builtins import string_or_bytes
 
 BLOCK_TAGS = [
     'div',
diff --git a/src/calibre/ebooks/unihandecode/jadecoder.py b/src/calibre/ebooks/unihandecode/jadecoder.py
index c143ac4f9e..635e35c8b5 100644
--- a/src/calibre/ebooks/unihandecode/jadecoder.py
+++ b/src/calibre/ebooks/unihandecode/jadecoder.py
@@ -17,10 +17,11 @@ Copyright (c) 2010 Hiroshi Miura
 '''
 
 import re
-from calibre.ebooks.unihandecode.unidecoder import Unidecoder
-from calibre.ebooks.unihandecode.unicodepoints import CODEPOINTS
+
 from calibre.ebooks.unihandecode.jacodepoints import CODEPOINTS as JACODES
 from calibre.ebooks.unihandecode.pykakasi.kakasi import kakasi
+from calibre.ebooks.unihandecode.unicodepoints import CODEPOINTS
+from calibre.ebooks.unihandecode.unidecoder import Unidecoder
 
 
 class Jadecoder(Unidecoder):
diff --git a/src/calibre/ebooks/unihandecode/krdecoder.py b/src/calibre/ebooks/unihandecode/krdecoder.py
index e4cbca94f8..1aaa415f99 100644
--- a/src/calibre/ebooks/unihandecode/krdecoder.py
+++ b/src/calibre/ebooks/unihandecode/krdecoder.py
@@ -8,9 +8,9 @@ Based on unidecoder.
 
 '''
 
-from calibre.ebooks.unihandecode.unidecoder import Unidecoder
 from calibre.ebooks.unihandecode.krcodepoints import CODEPOINTS as HANCODES
 from calibre.ebooks.unihandecode.unicodepoints import CODEPOINTS
+from calibre.ebooks.unihandecode.unidecoder import Unidecoder
 
 
 class Krdecoder(Unidecoder):
diff --git a/src/calibre/ebooks/unihandecode/pykakasi/__init__.py b/src/calibre/ebooks/unihandecode/pykakasi/__init__.py
index 705aced763..7900e91691 100644
--- a/src/calibre/ebooks/unihandecode/pykakasi/__init__.py
+++ b/src/calibre/ebooks/unihandecode/pykakasi/__init__.py
@@ -1,4 +1,5 @@
 from calibre.ebooks.unihandecode.pykakasi.kakasi import kakasi
+
 kakasi
 
 __all__ = ["pykakasi"]
diff --git a/src/calibre/ebooks/unihandecode/pykakasi/jisyo.py b/src/calibre/ebooks/unihandecode/pykakasi/jisyo.py
index 749ba30971..c4ff561f35 100644
--- a/src/calibre/ebooks/unihandecode/pykakasi/jisyo.py
+++ b/src/calibre/ebooks/unihandecode/pykakasi/jisyo.py
@@ -21,8 +21,8 @@ class jisyo :
         return self
 
     def __init__(self):
-        from calibre.utils.serialize import msgpack_loads
         from calibre.utils.resources import get_path as P
+        from calibre.utils.serialize import msgpack_loads
         if self.kanwadict is None:
             self.kanwadict = msgpack_loads(
                 P('localization/pykakasi/kanwadict2.calibre_msgpack', data=True))
diff --git a/src/calibre/ebooks/unihandecode/pykakasi/kakasi.py b/src/calibre/ebooks/unihandecode/pykakasi/kakasi.py
index 0429667f92..04db2fce30 100644
--- a/src/calibre/ebooks/unihandecode/pykakasi/kakasi.py
+++ b/src/calibre/ebooks/unihandecode/pykakasi/kakasi.py
@@ -21,8 +21,8 @@
 # */
 
 
-from calibre.ebooks.unihandecode.pykakasi.j2h import J2H
 from calibre.ebooks.unihandecode.pykakasi.h2a import H2a
+from calibre.ebooks.unihandecode.pykakasi.j2h import J2H
 from calibre.ebooks.unihandecode.pykakasi.k2a import K2a
 
 
diff --git a/src/calibre/ebooks/unihandecode/unidecoder.py b/src/calibre/ebooks/unihandecode/unidecoder.py
index 6a56ce5166..a4a3ba9a5a 100644
--- a/src/calibre/ebooks/unihandecode/unidecoder.py
+++ b/src/calibre/ebooks/unihandecode/unidecoder.py
@@ -58,6 +58,7 @@ it under the same terms as Perl itself.
 '''
 
 import re
+
 from calibre.ebooks.unihandecode.unicodepoints import CODEPOINTS
 from calibre.ebooks.unihandecode.zhcodepoints import CODEPOINTS as HANCODES
 
diff --git a/src/calibre/ebooks/unihandecode/vndecoder.py b/src/calibre/ebooks/unihandecode/vndecoder.py
index 2f6f89c11d..6f26b2fde1 100644
--- a/src/calibre/ebooks/unihandecode/vndecoder.py
+++ b/src/calibre/ebooks/unihandecode/vndecoder.py
@@ -7,9 +7,9 @@ Decode unicode text to an ASCII representation of the text in Vietnamese.
 
 '''
 
+from calibre.ebooks.unihandecode.unicodepoints import CODEPOINTS
 from calibre.ebooks.unihandecode.unidecoder import Unidecoder
 from calibre.ebooks.unihandecode.vncodepoints import CODEPOINTS as HANCODES
-from calibre.ebooks.unihandecode.unicodepoints import CODEPOINTS
 
 
 class Vndecoder(Unidecoder):
diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index 423791751f..fd501990dc 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -10,28 +10,71 @@ import sys
 import threading
 from contextlib import contextmanager, suppress
 from functools import lru_cache
-from qt.core import (
-    QApplication, QBuffer, QByteArray, QColor, QDateTime, QDesktopServices, QDialog,
-    QDialogButtonBox, QEvent, QFile, QFileDialog, QFileIconProvider, QFileInfo, QFont,
-    QFontDatabase, QFontInfo, QFontMetrics, QGuiApplication, QIcon, QImageReader,
-    QImageWriter, QIODevice, QLocale, QNetworkProxyFactory, QObject, QPalette,
-    QResource, QSettings, QSocketNotifier, QStringListModel, Qt, QThread, QTimer,
-    QTranslator, QUrl, QWidget, pyqtSignal, pyqtSlot,
-)
 from threading import Lock, RLock
 
+from qt.core import (
+    QApplication,
+    QBuffer,
+    QByteArray,
+    QColor,
+    QDateTime,
+    QDesktopServices,
+    QDialog,
+    QDialogButtonBox,
+    QEvent,
+    QFile,
+    QFileDialog,
+    QFileIconProvider,
+    QFileInfo,
+    QFont,
+    QFontDatabase,
+    QFontInfo,
+    QFontMetrics,
+    QGuiApplication,
+    QIcon,
+    QImageReader,
+    QImageWriter,
+    QIODevice,
+    QLocale,
+    QNetworkProxyFactory,
+    QObject,
+    QPalette,
+    QResource,
+    QSettings,
+    QSocketNotifier,
+    QStringListModel,
+    Qt,
+    QThread,
+    QTimer,
+    QTranslator,
+    QUrl,
+    QWidget,
+    pyqtSignal,
+    pyqtSlot,
+)
+
 import calibre.gui2.pyqt6_compat as pqc
 from calibre import as_unicode, prints
 from calibre.constants import (
-    DEBUG, __appname__ as APP_UID, __version__, builtin_colors_dark,
-    builtin_colors_light, config_dir, is_running_from_develop, isbsd, isfrozen, islinux,
-    ismacos, iswindows, isxp, numeric_version, plugins_loc,
+    DEBUG,
+    __version__,
+    builtin_colors_dark,
+    builtin_colors_light,
+    config_dir,
+    is_running_from_develop,
+    isbsd,
+    isfrozen,
+    islinux,
+    ismacos,
+    iswindows,
+    isxp,
+    numeric_version,
+    plugins_loc,
 )
+from calibre.constants import __appname__ as APP_UID
 from calibre.ebooks.metadata import MetaInformation
 from calibre.gui2.geometry import geometry_for_restore_as_dict
-from calibre.gui2.linux_file_dialogs import (
-    check_for_linux_native_dialogs, linux_native_dialog,
-)
+from calibre.gui2.linux_file_dialogs import check_for_linux_native_dialogs, linux_native_dialog
 from calibre.gui2.palette import PaletteManager
 from calibre.gui2.qt_file_dialogs import FileDialog
 from calibre.ptempfile import base_dir
@@ -41,7 +84,9 @@ from calibre.utils.date import UNDEFINED_DATE
 from calibre.utils.file_type_icons import EXT_MAP
 from calibre.utils.img import set_image_allocation_limit
 from calibre.utils.localization import get_lang
-from calibre.utils.resources import get_image_path as I, get_path as P, user_dir
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
+from calibre.utils.resources import user_dir
 from polyglot import queue
 from polyglot.builtins import iteritems, string_or_bytes
 
@@ -923,16 +968,12 @@ if not iswindows and not ismacos and 'CALIBRE_NO_NATIVE_FILEDIALOGS' not in os.e
     has_linux_file_dialog_helper = check_for_linux_native_dialogs()
 
 if has_windows_file_dialog_helper:
-    from calibre.gui2.win_file_dialogs import (
-        choose_dir, choose_files, choose_images, choose_save_file,
-    )
+    from calibre.gui2.win_file_dialogs import choose_dir, choose_files, choose_images, choose_save_file
 elif has_linux_file_dialog_helper:
     choose_dir, choose_files, choose_save_file, choose_images = map(
         linux_native_dialog, 'dir files save_file images'.split())
 else:
-    from calibre.gui2.qt_file_dialogs import (
-        choose_dir, choose_files, choose_images, choose_save_file,
-    )
+    from calibre.gui2.qt_file_dialogs import choose_dir, choose_files, choose_images, choose_save_file
     choose_files, choose_images, choose_dir, choose_save_file
 
 
diff --git a/src/calibre/gui2/actions/__init__.py b/src/calibre/gui2/actions/__init__.py
index 8510454af7..792863e8e8 100644
--- a/src/calibre/gui2/actions/__init__.py
+++ b/src/calibre/gui2/actions/__init__.py
@@ -8,9 +8,7 @@ __docformat__ = 'restructuredtext en'
 from functools import partial
 from zipfile import ZipFile
 
-from qt.core import (
-    QAction, QIcon, QKeySequence, QMenu, QObject, QPoint, QTimer, QToolButton,
-)
+from qt.core import QAction, QIcon, QKeySequence, QMenu, QObject, QPoint, QTimer, QToolButton
 
 from calibre import prints
 from calibre.constants import ismacos
diff --git a/src/calibre/gui2/actions/add.py b/src/calibre/gui2/actions/add.py
index e9b0f84786..79a710d8da 100644
--- a/src/calibre/gui2/actions/add.py
+++ b/src/calibre/gui2/actions/add.py
@@ -8,16 +8,14 @@ __docformat__ = 'restructuredtext en'
 import os
 from collections import defaultdict
 from functools import partial
+
 from qt.core import QApplication, QDialog, QPixmap, QTimer
 
 from calibre import as_unicode, guess_type, prepare_string_for_xml
 from calibre.constants import iswindows
 from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.ebooks.metadata import MetaInformation, normalize_isbn
-from calibre.gui2 import (
-    choose_dir, choose_files, choose_files_and_remember_all_files, error_dialog, gprefs,
-    info_dialog, question_dialog, warning_dialog,
-)
+from calibre.gui2 import choose_dir, choose_files, choose_files_and_remember_all_files, error_dialog, gprefs, info_dialog, question_dialog, warning_dialog
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.add_empty_book import AddEmptyBookDialog
 from calibre.gui2.dialogs.confirm_delete import confirm
diff --git a/src/calibre/gui2/actions/all_actions.py b/src/calibre/gui2/actions/all_actions.py
index ba06a9452d..2ef657f8cd 100644
--- a/src/calibre/gui2/actions/all_actions.py
+++ b/src/calibre/gui2/actions/all_actions.py
@@ -4,7 +4,7 @@
 from functools import partial
 from math import ceil
 
-from qt.core import QIcon, QMenu, QToolButton, Qt
+from qt.core import QIcon, QMenu, Qt, QToolButton
 
 from calibre.gui2.actions import InterfaceAction, show_menu_under_widget
 from calibre.gui2.preferences.toolbar import AllModel, CurrentModel
diff --git a/src/calibre/gui2/actions/annotate.py b/src/calibre/gui2/actions/annotate.py
index 42fc554c01..8f8fdb0dac 100644
--- a/src/calibre/gui2/actions/annotate.py
+++ b/src/calibre/gui2/actions/annotate.py
@@ -6,11 +6,11 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import pyqtSignal, QModelIndex, QThread, Qt
+from qt.core import QModelIndex, Qt, QThread, pyqtSignal
 
+from calibre.devices.usbms.device import Device
 from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
-from calibre.devices.usbms.device import Device
 from calibre.gui2.dialogs.progress import ProgressDialog
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/gui2/actions/catalog.py b/src/calibre/gui2/actions/catalog.py
index ba147c8039..536dc684d6 100644
--- a/src/calibre/gui2/actions/catalog.py
+++ b/src/calibre/gui2/actions/catalog.py
@@ -5,15 +5,17 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, os, shutil
+import os
+import re
+import shutil
 
 from qt.core import QModelIndex
 
+from calibre import sanitize_file_name
 from calibre.gui2 import choose_dir, error_dialog, warning_dialog
+from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.tools import generate_catalog
 from calibre.utils.config import dynamic
-from calibre.gui2.actions import InterfaceAction
-from calibre import sanitize_file_name
 
 
 class GenerateCatalogAction(InterfaceAction):
diff --git a/src/calibre/gui2/actions/choose_library.py b/src/calibre/gui2/actions/choose_library.py
index f006b44457..087e5f5d4a 100644
--- a/src/calibre/gui2/actions/choose_library.py
+++ b/src/calibre/gui2/actions/choose_library.py
@@ -10,19 +10,39 @@ import sys
 import weakref
 from contextlib import suppress
 from functools import lru_cache, partial
+
 from qt.core import (
-    QAction, QCoreApplication, QDialog, QDialogButtonBox, QGridLayout, QIcon,
-    QInputDialog, QLabel, QLineEdit, QMenu, QSize, Qt, QTimer, QToolButton, QVBoxLayout,
+    QAction,
+    QCoreApplication,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QIcon,
+    QInputDialog,
+    QLabel,
+    QLineEdit,
+    QMenu,
+    QSize,
+    Qt,
+    QTimer,
+    QToolButton,
+    QVBoxLayout,
     pyqtSignal,
 )
 
 from calibre import isbytestring, sanitize_file_name
-from calibre.constants import (
-    config_dir, filesystem_encoding, get_portable_base, isportable, iswindows,
-)
+from calibre.constants import config_dir, filesystem_encoding, get_portable_base, isportable, iswindows
 from calibre.gui2 import (
-    Dispatcher, choose_dir, choose_images, error_dialog, gprefs, info_dialog,
-    open_local_file, pixmap_to_data, question_dialog, warning_dialog,
+    Dispatcher,
+    choose_dir,
+    choose_images,
+    error_dialog,
+    gprefs,
+    info_dialog,
+    open_local_file,
+    pixmap_to_data,
+    question_dialog,
+    warning_dialog,
 )
 from calibre.gui2.actions import InterfaceAction
 from calibre.library import current_library_name
diff --git a/src/calibre/gui2/actions/convert.py b/src/calibre/gui2/actions/convert.py
index 6278b38c49..8f5297c813 100644
--- a/src/calibre/gui2/actions/convert.py
+++ b/src/calibre/gui2/actions/convert.py
@@ -7,6 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 from functools import partial
+
 from qt.core import QModelIndex
 
 from calibre.customize.ui import plugin_for_input_format, run_plugins_on_postconvert
diff --git a/src/calibre/gui2/actions/copy_to_library.py b/src/calibre/gui2/actions/copy_to_library.py
index 180fc0ddf7..a17d5d1a19 100644
--- a/src/calibre/gui2/actions/copy_to_library.py
+++ b/src/calibre/gui2/actions/copy_to_library.py
@@ -9,19 +9,34 @@ import os
 from collections import defaultdict
 from contextlib import closing
 from functools import partial
-from qt.core import (
-    QAbstractItemView, QApplication, QCheckBox, QDialog, QDialogButtonBox, QFormLayout,
-    QGridLayout, QHBoxLayout, QIcon, QLabel, QLineEdit, QListWidget, QListWidgetItem,
-    QScrollArea, QSize, Qt, QToolButton, QVBoxLayout, QWidget,
-)
 from threading import Thread
 
+from qt.core import (
+    QAbstractItemView,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QScrollArea,
+    QSize,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+)
+
 from calibre import as_unicode
 from calibre.constants import ismacos
 from calibre.db.copy_to_library import copy_one_book
-from calibre.gui2 import (
-    Dispatcher, choose_dir, error_dialog, gprefs, info_dialog, warning_dialog,
-)
+from calibre.gui2 import Dispatcher, choose_dir, error_dialog, gprefs, info_dialog, warning_dialog
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.actions.choose_library import library_qicon
 from calibre.gui2.dialogs.progress import ProgressDialog
diff --git a/src/calibre/gui2/actions/delete.py b/src/calibre/gui2/actions/delete.py
index 2bcb049a9a..db6aa5e9fd 100644
--- a/src/calibre/gui2/actions/delete.py
+++ b/src/calibre/gui2/actions/delete.py
@@ -7,6 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 from collections import Counter
 from functools import partial
+
 from qt.core import QDialog, QModelIndex, QObject, QTimer
 
 from calibre.constants import ismacos
@@ -14,9 +15,7 @@ from calibre.gui2 import Aborted, error_dialog
 from calibre.gui2.actions import InterfaceActionWithLibraryDrop
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.dialogs.confirm_delete_location import confirm_location
-from calibre.gui2.dialogs.delete_matching_from_device import (
-    DeleteMatchingFromDeviceDialog,
-)
+from calibre.gui2.dialogs.delete_matching_from_device import DeleteMatchingFromDeviceDialog
 from calibre.gui2.widgets import BusyCursor
 from calibre.gui2.widgets2 import MessagePopup
 from calibre.utils.localization import ngettext
diff --git a/src/calibre/gui2/actions/edit_metadata.py b/src/calibre/gui2/actions/edit_metadata.py
index c42de10e91..c2473bba35 100644
--- a/src/calibre/gui2/actions/edit_metadata.py
+++ b/src/calibre/gui2/actions/edit_metadata.py
@@ -11,9 +11,8 @@ import shutil
 from contextlib import contextmanager
 from functools import partial
 from io import BytesIO
-from qt.core import (
-    QAction, QApplication, QDialog, QIcon, QMenu, QMimeData, QModelIndex, QTimer, QUrl,
-)
+
+from qt.core import QAction, QApplication, QDialog, QIcon, QMenu, QMimeData, QModelIndex, QTimer, QUrl
 
 from calibre.db.errors import NoSuchFormat
 from calibre.ebooks.metadata import authors_to_string
diff --git a/src/calibre/gui2/actions/embed.py b/src/calibre/gui2/actions/embed.py
index cd7f574ae0..e5cd266f05 100644
--- a/src/calibre/gui2/actions/embed.py
+++ b/src/calibre/gui2/actions/embed.py
@@ -5,6 +5,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
+
 from qt.core import QProgressDialog, Qt, QTimer
 
 from calibre import force_unicode
diff --git a/src/calibre/gui2/actions/fetch_news.py b/src/calibre/gui2/actions/fetch_news.py
index 6ad68f068c..b143987676 100644
--- a/src/calibre/gui2/actions/fetch_news.py
+++ b/src/calibre/gui2/actions/fetch_news.py
@@ -11,8 +11,8 @@ from functools import partial
 from qt.core import Qt
 
 from calibre.gui2 import Dispatcher
-from calibre.gui2.tools import fetch_scheduled_recipe
 from calibre.gui2.actions import InterfaceAction
+from calibre.gui2.tools import fetch_scheduled_recipe
 
 
 class FetchNewsAction(InterfaceAction):
diff --git a/src/calibre/gui2/actions/layout_actions.py b/src/calibre/gui2/actions/layout_actions.py
index ccae8f3b89..820ce0c73c 100644
--- a/src/calibre/gui2/actions/layout_actions.py
+++ b/src/calibre/gui2/actions/layout_actions.py
@@ -3,8 +3,8 @@
 
 from enum import Enum
 from functools import partial
-from qt.core import (QComboBox, QDialog, QDialogButtonBox, QFormLayout, QIcon,
-                     QLabel, QMenu, QToolButton, QVBoxLayout)
+
+from qt.core import QComboBox, QDialog, QDialogButtonBox, QFormLayout, QIcon, QLabel, QMenu, QToolButton, QVBoxLayout
 
 from calibre.gui2 import error_dialog, gprefs, question_dialog
 from calibre.gui2.actions import InterfaceAction, show_menu_under_widget
diff --git a/src/calibre/gui2/actions/mark_books.py b/src/calibre/gui2/actions/mark_books.py
index 1733253707..02c7309475 100644
--- a/src/calibre/gui2/actions/mark_books.py
+++ b/src/calibre/gui2/actions/mark_books.py
@@ -5,10 +5,8 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
-from qt.core import (
-    QApplication, QDialog, QDialogButtonBox, QEvent, QGridLayout, QIcon, QLabel, QMenu,
-    QPushButton, Qt,
-)
+
+from qt.core import QApplication, QDialog, QDialogButtonBox, QEvent, QGridLayout, QIcon, QLabel, QMenu, QPushButton, Qt
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceActionWithLibraryDrop
diff --git a/src/calibre/gui2/actions/plugin_updates.py b/src/calibre/gui2/actions/plugin_updates.py
index 39e4b383ad..2710a180a5 100644
--- a/src/calibre/gui2/actions/plugin_updates.py
+++ b/src/calibre/gui2/actions/plugin_updates.py
@@ -5,10 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Grant Drake <grant.drake@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import QApplication, Qt, QIcon
+from qt.core import QApplication, QIcon, Qt
+
 from calibre.gui2.actions import InterfaceAction
-from calibre.gui2.dialogs.plugin_updater import (PluginUpdaterDialog,
-                                                 FILTER_ALL, FILTER_UPDATE_AVAILABLE)
+from calibre.gui2.dialogs.plugin_updater import FILTER_ALL, FILTER_UPDATE_AVAILABLE, PluginUpdaterDialog
 
 
 class PluginUpdaterAction(InterfaceAction):
diff --git a/src/calibre/gui2/actions/polish.py b/src/calibre/gui2/actions/polish.py
index 71a9e28bf1..741d90a528 100644
--- a/src/calibre/gui2/actions/polish.py
+++ b/src/calibre/gui2/actions/polish.py
@@ -11,10 +11,25 @@ import textwrap
 import weakref
 from collections import OrderedDict
 from functools import partial
+
 from qt.core import (
-    QApplication, QCheckBox, QDialog, QDialogButtonBox, QFrame, QGridLayout, QIcon,
-    QInputDialog, QLabel, QMenu, QModelIndex, QSize, QSizePolicy, QSpacerItem, Qt,
-    QTextEdit, QTimer,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QGridLayout,
+    QIcon,
+    QInputDialog,
+    QLabel,
+    QMenu,
+    QModelIndex,
+    QSize,
+    QSizePolicy,
+    QSpacerItem,
+    Qt,
+    QTextEdit,
+    QTimer,
 )
 
 from calibre.gui2 import Dispatcher, error_dialog, gprefs, question_dialog
diff --git a/src/calibre/gui2/actions/preferences.py b/src/calibre/gui2/actions/preferences.py
index 36eee6d8f8..d46311efca 100644
--- a/src/calibre/gui2/actions/preferences.py
+++ b/src/calibre/gui2/actions/preferences.py
@@ -9,11 +9,11 @@ from functools import partial
 
 from qt.core import QIcon, Qt
 
+from calibre.constants import DEBUG, ismacos
 from calibre.customize.ui import preferences_plugins
+from calibre.gui2 import error_dialog, show_restart_warning
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.preferences.main import Preferences
-from calibre.gui2 import error_dialog, show_restart_warning
-from calibre.constants import DEBUG, ismacos
 
 
 class PreferencesAction(InterfaceAction):
@@ -67,8 +67,7 @@ class PreferencesAction(InterfaceAction):
 
 
     def get_plugins(self):
-        from calibre.gui2.dialogs.plugin_updater import (PluginUpdaterDialog,
-                FILTER_NOT_INSTALLED)
+        from calibre.gui2.dialogs.plugin_updater import FILTER_NOT_INSTALLED, PluginUpdaterDialog
         d = PluginUpdaterDialog(self.gui,
                 initial_filter=FILTER_NOT_INSTALLED)
         d.exec()
diff --git a/src/calibre/gui2/actions/save_to_disk.py b/src/calibre/gui2/actions/save_to_disk.py
index 323cbafd8f..038ccd8ca2 100644
--- a/src/calibre/gui2/actions/save_to_disk.py
+++ b/src/calibre/gui2/actions/save_to_disk.py
@@ -5,12 +5,13 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, numbers
+import numbers
+import os
 from functools import partial
 
-from calibre.utils.config import prefs
-from calibre.gui2 import error_dialog, Dispatcher, choose_dir
+from calibre.gui2 import Dispatcher, choose_dir, error_dialog
 from calibre.gui2.actions import InterfaceAction
+from calibre.utils.config import prefs
 from polyglot.builtins import itervalues
 
 
diff --git a/src/calibre/gui2/actions/show_book_details.py b/src/calibre/gui2/actions/show_book_details.py
index 6cf2f74d3b..77335f6f9e 100644
--- a/src/calibre/gui2/actions/show_book_details.py
+++ b/src/calibre/gui2/actions/show_book_details.py
@@ -7,9 +7,9 @@ __docformat__ = 'restructuredtext en'
 
 from qt.core import Qt, sip
 
+from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.book_info import BookInfo, DialogNumbers
-from calibre.gui2 import error_dialog
 
 
 class ShowBookDetailsAction(InterfaceAction):
diff --git a/src/calibre/gui2/actions/show_quickview.py b/src/calibre/gui2/actions/show_quickview.py
index dc77e14733..a0f4fe5ee6 100644
--- a/src/calibre/gui2/actions/show_quickview.py
+++ b/src/calibre/gui2/actions/show_quickview.py
@@ -8,10 +8,9 @@ __docformat__ = 'restructuredtext en'
 
 from qt.core import QAction, QTimer
 
+from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.quickview import Quickview
-from calibre.gui2 import error_dialog
-
 
 current_qv_action_pi = None
 
diff --git a/src/calibre/gui2/actions/show_template_tester.py b/src/calibre/gui2/actions/show_template_tester.py
index be163e8639..dbd2c9da8e 100644
--- a/src/calibre/gui2/actions/show_template_tester.py
+++ b/src/calibre/gui2/actions/show_template_tester.py
@@ -5,9 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
+from calibre.gui2 import error_dialog
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
-from calibre.gui2 import error_dialog
 
 
 class ShowTemplateTesterAction(InterfaceAction):
diff --git a/src/calibre/gui2/actions/sort.py b/src/calibre/gui2/actions/sort.py
index 02e42b6f37..82ab67e7b1 100644
--- a/src/calibre/gui2/actions/sort.py
+++ b/src/calibre/gui2/actions/sort.py
@@ -6,9 +6,21 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from contextlib import suppress
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QAction, QDialog, QDialogButtonBox, QIcon, QListWidget,
-    QListWidgetItem, QMenu, QSize, Qt, QToolButton, QVBoxLayout, pyqtSignal,
+    QAbstractItemView,
+    QAction,
+    QDialog,
+    QDialogButtonBox,
+    QIcon,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QSize,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    pyqtSignal,
 )
 
 from calibre.gui2.actions import InterfaceAction, show_menu_under_widget
diff --git a/src/calibre/gui2/actions/toc_edit.py b/src/calibre/gui2/actions/toc_edit.py
index 1f235b22af..85f8e15a8f 100644
--- a/src/calibre/gui2/actions/toc_edit.py
+++ b/src/calibre/gui2/actions/toc_edit.py
@@ -8,9 +8,8 @@ __docformat__ = 'restructuredtext en'
 import os
 from collections import OrderedDict
 from itertools import count
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QTimer,
-)
+
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QTimer
 
 from calibre.gui2 import error_dialog, gprefs, question_dialog
 from calibre.gui2.actions import InterfaceActionWithLibraryDrop
diff --git a/src/calibre/gui2/actions/tweak_epub.py b/src/calibre/gui2/actions/tweak_epub.py
index ac2087429e..a6d15ebedc 100644
--- a/src/calibre/gui2/actions/tweak_epub.py
+++ b/src/calibre/gui2/actions/tweak_epub.py
@@ -6,9 +6,8 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import time
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QLabel, Qt, QVBoxLayout,
-)
+
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QLabel, Qt, QVBoxLayout
 
 from calibre.gui2 import error_dialog, question_dialog
 from calibre.gui2.actions import InterfaceActionWithLibraryDrop
diff --git a/src/calibre/gui2/actions/unpack_book.py b/src/calibre/gui2/actions/unpack_book.py
index 908736729a..d32f09f4f4 100644
--- a/src/calibre/gui2/actions/unpack_book.py
+++ b/src/calibre/gui2/actions/unpack_book.py
@@ -8,10 +8,8 @@ __docformat__ = 'restructuredtext en'
 import os
 import shutil
 import weakref
-from qt.core import (
-    QDialog, QFrame, QGridLayout, QGroupBox, QHBoxLayout, QIcon, QLabel, QPushButton,
-    QRadioButton, QSize, QTimer, QVBoxLayout,
-)
+
+from qt.core import QDialog, QFrame, QGridLayout, QGroupBox, QHBoxLayout, QIcon, QLabel, QPushButton, QRadioButton, QSize, QTimer, QVBoxLayout
 
 from calibre import as_unicode
 from calibre.constants import ismacos
diff --git a/src/calibre/gui2/actions/view.py b/src/calibre/gui2/actions/view.py
index d7cf1d4b16..04dee1c19b 100644
--- a/src/calibre/gui2/actions/view.py
+++ b/src/calibre/gui2/actions/view.py
@@ -9,14 +9,12 @@ import json
 import os
 import time
 from functools import partial
+
 from qt.core import QAction, QDialog, QIcon, pyqtSignal
 
 from calibre.constants import ismacos, iswindows
 from calibre.db.constants import DATA_DIR_NAME
-from calibre.gui2 import (
-    Dispatcher, config, elided_text, error_dialog, info_dialog, open_local_file,
-    question_dialog,
-)
+from calibre.gui2 import Dispatcher, config, elided_text, error_dialog, info_dialog, open_local_file, question_dialog
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.choose_format import ChooseFormatDialog
 from calibre.ptempfile import PersistentTemporaryFile
diff --git a/src/calibre/gui2/actions/virtual_library.py b/src/calibre/gui2/actions/virtual_library.py
index baf0c8b7b7..9786f3058e 100644
--- a/src/calibre/gui2/actions/virtual_library.py
+++ b/src/calibre/gui2/actions/virtual_library.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 # License: GPLv3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
-from qt.core import QToolButton, QAction
+from qt.core import QAction, QToolButton
 
 from calibre.gui2.actions import InterfaceAction
 
diff --git a/src/calibre/gui2/add.py b/src/calibre/gui2/add.py
index 2327a0334f..1ff54be95e 100644
--- a/src/calibre/gui2/add.py
+++ b/src/calibre/gui2/add.py
@@ -13,9 +13,10 @@ import traceback
 import weakref
 from collections import OrderedDict
 from io import BytesIO
-from qt.core import QObject, Qt, pyqtSignal
 from threading import Thread
 
+from qt.core import QObject, Qt, pyqtSignal
+
 from calibre import as_unicode, prints
 from calibre.constants import DEBUG, filesystem_encoding, ismacos, iswindows
 from calibre.customize.ui import run_plugins_on_postadd, run_plugins_on_postimport
diff --git a/src/calibre/gui2/add_filters.py b/src/calibre/gui2/add_filters.py
index 0293487442..cdc3d50ec3 100644
--- a/src/calibre/gui2/add_filters.py
+++ b/src/calibre/gui2/add_filters.py
@@ -4,13 +4,14 @@
 
 from collections import OrderedDict
 
-from calibre.db.adding import compile_glob, filter_filename, compile_rule
-from calibre.gui2 import elided_text, Application, error_dialog
-from calibre.gui2.tag_mapper import (
-    RuleEdit as RuleEditBase, RuleEditDialog as
-    RuleEditDialogBase, RuleItem as RuleItemBase, Rules as RulesBase,
-    Tester as TesterBase, RulesDialog as RulesDialogBase
-)
+from calibre.db.adding import compile_glob, compile_rule, filter_filename
+from calibre.gui2 import Application, elided_text, error_dialog
+from calibre.gui2.tag_mapper import RuleEdit as RuleEditBase
+from calibre.gui2.tag_mapper import RuleEditDialog as RuleEditDialogBase
+from calibre.gui2.tag_mapper import RuleItem as RuleItemBase
+from calibre.gui2.tag_mapper import Rules as RulesBase
+from calibre.gui2.tag_mapper import RulesDialog as RulesDialogBase
+from calibre.gui2.tag_mapper import Tester as TesterBase
 from calibre.utils.config import JSONConfig
 
 add_filters = JSONConfig('add-filter-rules')
diff --git a/src/calibre/gui2/author_mapper.py b/src/calibre/gui2/author_mapper.py
index 3fe9395361..67fcbd5b2a 100644
--- a/src/calibre/gui2/author_mapper.py
+++ b/src/calibre/gui2/author_mapper.py
@@ -7,11 +7,12 @@ from collections import OrderedDict
 from calibre.ebooks.metadata import authors_to_string, string_to_authors
 from calibre.ebooks.metadata.author_mapper import compile_rules, map_authors
 from calibre.gui2 import Application, elided_text
-from calibre.gui2.tag_mapper import (
-    RuleEdit as RuleEditBase, RuleEditDialog as RuleEditDialogBase,
-    RuleItem as RuleItemBase, Rules as RulesBase, RulesDialog as RulesDialogBase,
-    Tester as TesterBase,
-)
+from calibre.gui2.tag_mapper import RuleEdit as RuleEditBase
+from calibre.gui2.tag_mapper import RuleEditDialog as RuleEditDialogBase
+from calibre.gui2.tag_mapper import RuleItem as RuleItemBase
+from calibre.gui2.tag_mapper import Rules as RulesBase
+from calibre.gui2.tag_mapper import RulesDialog as RulesDialogBase
+from calibre.gui2.tag_mapper import Tester as TesterBase
 from calibre.utils.config import JSONConfig
 
 author_maps = JSONConfig('author-mapping-rules')
diff --git a/src/calibre/gui2/auto_add.py b/src/calibre/gui2/auto_add.py
index e78c9070be..d1cae5e22c 100644
--- a/src/calibre/gui2/auto_add.py
+++ b/src/calibre/gui2/auto_add.py
@@ -5,11 +5,10 @@ import os
 import shutil
 import tempfile
 import time
-from qt.core import (
-    QApplication, QCursor, QFileSystemWatcher, QObject, Qt, QTimer, pyqtSignal,
-)
 from threading import Event, Thread
 
+from qt.core import QApplication, QCursor, QFileSystemWatcher, QObject, Qt, QTimer, pyqtSignal
+
 from calibre import prints
 from calibre.db.adding import compile_rule, filter_filename
 from calibre.ebooks import BOOK_EXTENSIONS
@@ -262,9 +261,7 @@ class AutoAdder(QObject):
                 from calibre.ebooks.metadata.tag_mapper import map_tags
                 mi.tags = map_tags(mi.tags, gprefs['tag_map_on_add_rules'])
             if gprefs.get('author_map_on_add_rules'):
-                from calibre.ebooks.metadata.author_mapper import (
-                    compile_rules, map_authors,
-                )
+                from calibre.ebooks.metadata.author_mapper import compile_rules, map_authors
                 new_authors = map_authors(mi.authors, compile_rules(gprefs['author_map_on_add_rules']))
                 if new_authors != mi.authors:
                     mi.authors = new_authors
diff --git a/src/calibre/gui2/bars.py b/src/calibre/gui2/bars.py
index 7108eafedc..f9070b39c2 100644
--- a/src/calibre/gui2/bars.py
+++ b/src/calibre/gui2/bars.py
@@ -6,16 +6,35 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from functools import partial
+
 from qt.core import (
-    Qt, QAction, QMenu, QObject, QToolBar, QToolButton, QSize, pyqtSignal, QKeySequence, QMenuBar,
-    QTimer, QPropertyAnimation, QEasingCurve, pyqtProperty, QPainter, QWidget, QPalette, sip,
-    QHBoxLayout, QFrame)
+    QAction,
+    QEasingCurve,
+    QFrame,
+    QHBoxLayout,
+    QKeySequence,
+    QMenu,
+    QMenuBar,
+    QObject,
+    QPainter,
+    QPalette,
+    QPropertyAnimation,
+    QSize,
+    Qt,
+    QTimer,
+    QToolBar,
+    QToolButton,
+    QWidget,
+    pyqtProperty,
+    pyqtSignal,
+    sip,
+)
 
 from calibre.constants import ismacos
-from calibre.gui2 import gprefs, native_menubar_defaults, config
+from calibre.gui2 import config, gprefs, native_menubar_defaults
 from calibre.gui2.throbber import ThrobbingButton
-from polyglot.builtins import itervalues
 from calibre.gui2.widgets2 import RightClickButton
+from polyglot.builtins import itervalues
 
 
 class RevealBar(QWidget):  # {{{
diff --git a/src/calibre/gui2/book_details.py b/src/calibre/gui2/book_details.py
index 908ea7f3ae..1e1106e4c9 100644
--- a/src/calibre/gui2/book_details.py
+++ b/src/calibre/gui2/book_details.py
@@ -7,11 +7,33 @@ import re
 from collections import namedtuple
 from contextlib import suppress
 from functools import lru_cache, partial
+
 from qt.core import (
-    QAction, QApplication, QClipboard, QColor, QDialog, QEasingCurve, QIcon,
-    QKeySequence, QMenu, QMimeData, QPainter, QPalette, QPen, QPixmap,
-    QPropertyAnimation, QRect, QSize, QSizePolicy, QSplitter, Qt, QTimer, QUrl, QWidget,
-    pyqtProperty, pyqtSignal,
+    QAction,
+    QApplication,
+    QClipboard,
+    QColor,
+    QDialog,
+    QEasingCurve,
+    QIcon,
+    QKeySequence,
+    QMenu,
+    QMimeData,
+    QPainter,
+    QPalette,
+    QPen,
+    QPixmap,
+    QPropertyAnimation,
+    QRect,
+    QSize,
+    QSizePolicy,
+    QSplitter,
+    Qt,
+    QTimer,
+    QUrl,
+    QWidget,
+    pyqtProperty,
+    pyqtSignal,
 )
 
 from calibre import fit_image, sanitize_file_name
@@ -20,18 +42,11 @@ from calibre.db.constants import DATA_DIR_NAME, DATA_FILE_PATTERN, RESOURCE_URL_
 from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.ebooks.metadata.book.base import Metadata, field_metadata
 from calibre.ebooks.metadata.book.render import mi_to_html
-from calibre.ebooks.metadata.search_internet import (
-    all_author_searches, all_book_searches, name_for, url_for_author_search,
-    url_for_book_search,
-)
-from calibre.gui2 import (
-    NO_URL_FORMATTING, choose_save_file, config, default_author_link, gprefs,
-    pixmap_to_data, question_dialog, rating_font, safe_open_url,
-)
-from calibre.gui2.dialogs.confirm_delete import confirm, confirm as confirm_delete
-from calibre.gui2.dnd import (
-    dnd_get_files, dnd_get_image, dnd_has_extension, dnd_has_image, image_extensions,
-)
+from calibre.ebooks.metadata.search_internet import all_author_searches, all_book_searches, name_for, url_for_author_search, url_for_book_search
+from calibre.gui2 import NO_URL_FORMATTING, choose_save_file, config, default_author_link, gprefs, pixmap_to_data, question_dialog, rating_font, safe_open_url
+from calibre.gui2.dialogs.confirm_delete import confirm
+from calibre.gui2.dialogs.confirm_delete import confirm as confirm_delete
+from calibre.gui2.dnd import dnd_get_files, dnd_get_image, dnd_has_extension, dnd_has_image, image_extensions
 from calibre.gui2.widgets2 import HTMLDisplay
 from calibre.startup import connect_lambda
 from calibre.utils.config import tweaks
diff --git a/src/calibre/gui2/catalog/catalog_bibtex.py b/src/calibre/gui2/catalog/catalog_bibtex.py
index 7fb17f6c1a..af41c91835 100644
--- a/src/calibre/gui2/catalog/catalog_bibtex.py
+++ b/src/calibre/gui2/catalog/catalog_bibtex.py
@@ -6,7 +6,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import QWidget, QListWidgetItem
+from qt.core import QListWidgetItem, QWidget
 
 from calibre.gui2 import gprefs
 from calibre.gui2.catalog.catalog_bibtex_ui import Ui_Form
diff --git a/src/calibre/gui2/catalog/catalog_csv_xml.py b/src/calibre/gui2/catalog/catalog_csv_xml.py
index 207c7dccfd..055ea5f543 100644
--- a/src/calibre/gui2/catalog/catalog_csv_xml.py
+++ b/src/calibre/gui2/catalog/catalog_csv_xml.py
@@ -5,10 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import (
-    QAbstractItemView, QHBoxLayout, QLabel, QListWidget, QListWidgetItem, QPushButton,
-    Qt, QVBoxLayout, QWidget,
-)
+from qt.core import QAbstractItemView, QHBoxLayout, QLabel, QListWidget, QListWidgetItem, QPushButton, Qt, QVBoxLayout, QWidget
 
 from calibre.constants import ismacos
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/catalog/catalog_epub_mobi.py b/src/calibre/gui2/catalog/catalog_epub_mobi.py
index 73f92bfed4..16172cbb97 100644
--- a/src/calibre/gui2/catalog/catalog_epub_mobi.py
+++ b/src/calibre/gui2/catalog/catalog_epub_mobi.py
@@ -5,21 +5,39 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import re, sys
-
+import re
+import sys
 from functools import partial
 
+from qt.core import (
+    QAbstractItemView,
+    QCheckBox,
+    QComboBox,
+    QDoubleSpinBox,
+    QIcon,
+    QInputDialog,
+    QLineEdit,
+    QRadioButton,
+    QSize,
+    QSizePolicy,
+    Qt,
+    QTableWidget,
+    QTableWidgetItem,
+    QTextEdit,
+    QToolButton,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    sip,
+)
+
 from calibre.ebooks.conversion.config import load_defaults
-from calibre.gui2 import gprefs, open_url, question_dialog, error_dialog
+from calibre.gui2 import error_dialog, gprefs, open_url, question_dialog
 from calibre.utils.config import JSONConfig
 from calibre.utils.icu import sort_key
 from calibre.utils.localization import localize_user_manual_link
 
 from .catalog_epub_mobi_ui import Ui_Form
-from qt.core import (Qt, QAbstractItemView, QCheckBox, QComboBox,
-        QDoubleSpinBox, QIcon, QInputDialog, QLineEdit, QRadioButton,
-        QSize, QSizePolicy, QTableWidget, QTableWidgetItem, QTextEdit, QToolButton,
-        QUrl, QVBoxLayout, QWidget, sip)
 
 
 class PluginWidget(QWidget,Ui_Form):
@@ -1096,7 +1114,7 @@ class GenericRulesTable(QTableWidget):
         # Format of rules list is different if default values vs retrieved JSON
         # Hack to normalize list style
         rules = self.rules
-        if rules and type(rules[0]) is list:
+        if rules and isinstance(rules[0], list):
             rules = rules[0]
         self.setFocus()
         rules = sorted(rules, key=lambda k: k['ordinal'])
diff --git a/src/calibre/gui2/central.py b/src/calibre/gui2/central.py
index a1ef62e457..5bbe0132de 100644
--- a/src/calibre/gui2/central.py
+++ b/src/calibre/gui2/central.py
@@ -5,10 +5,27 @@ from contextlib import suppress
 from copy import copy
 from dataclasses import asdict, dataclass, fields
 from enum import Enum, auto
+
 from qt.core import (
-    QAction, QDialog, QHBoxLayout, QIcon, QKeySequence, QLabel, QMainWindow, QPalette,
-    QPointF, QSize, QSizePolicy, QStyle, QStyleOption, QStylePainter, Qt, QToolButton,
-    QVBoxLayout, QWidget, pyqtSignal,
+    QAction,
+    QDialog,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QMainWindow,
+    QPalette,
+    QPointF,
+    QSize,
+    QSizePolicy,
+    QStyle,
+    QStyleOption,
+    QStylePainter,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.gui2 import Application, config, gprefs
diff --git a/src/calibre/gui2/changes.py b/src/calibre/gui2/changes.py
index 07f79e83f1..ad5831850b 100644
--- a/src/calibre/gui2/changes.py
+++ b/src/calibre/gui2/changes.py
@@ -2,10 +2,7 @@
 # License: GPLv3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from calibre.srv.changes import (
-    BooksAdded, BooksDeleted, FormatsAdded, FormatsRemoved, MetadataChanged,
-    SavedSearchesChanged
-)
+from calibre.srv.changes import BooksAdded, BooksDeleted, FormatsAdded, FormatsRemoved, MetadataChanged, SavedSearchesChanged
 
 
 def handle_changes(changes, gui=None):
diff --git a/src/calibre/gui2/comments_editor.py b/src/calibre/gui2/comments_editor.py
index 0016cc274d..bf8413951c 100644
--- a/src/calibre/gui2/comments_editor.py
+++ b/src/calibre/gui2/comments_editor.py
@@ -9,25 +9,71 @@ import weakref
 from collections import defaultdict
 from contextlib import contextmanager
 from functools import partial
+from threading import Thread
+
 from html5_parser import parse
 from lxml import html
 from qt.core import (
-    QAction, QApplication, QBrush, QByteArray, QCheckBox, QColor, QColorDialog, QDialog,
-    QDialogButtonBox, QFont, QFontInfo, QFontMetrics, QFormLayout, QHBoxLayout, QIcon,
-    QKeySequence, QLabel, QLineEdit, QMenu, QPalette, QPlainTextEdit, QPointF,
-    QPushButton, QSize, QSpinBox, QSyntaxHighlighter, Qt, QTabWidget, QTextBlockFormat,
-    QTextCharFormat, QTextCursor, QTextDocument, QTextEdit, QTextFormat,
-    QTextFrameFormat, QTextImageFormat, QTextListFormat, QTimer, QToolButton, QUrl,
-    QVBoxLayout, QWidget, pyqtSignal, pyqtSlot,
+    QAction,
+    QApplication,
+    QBrush,
+    QByteArray,
+    QCheckBox,
+    QColor,
+    QColorDialog,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFontInfo,
+    QFontMetrics,
+    QFormLayout,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QLineEdit,
+    QMenu,
+    QPalette,
+    QPlainTextEdit,
+    QPointF,
+    QPushButton,
+    QSize,
+    QSpinBox,
+    QSyntaxHighlighter,
+    Qt,
+    QTabWidget,
+    QTextBlockFormat,
+    QTextCharFormat,
+    QTextCursor,
+    QTextDocument,
+    QTextEdit,
+    QTextFormat,
+    QTextFrameFormat,
+    QTextImageFormat,
+    QTextListFormat,
+    QTimer,
+    QToolButton,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+    pyqtSlot,
 )
-from threading import Thread
 
 from calibre import browser, fit_image, xml_replace_entities
 from calibre.db.constants import DATA_DIR_NAME
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.gui2 import (
-    NO_URL_FORMATTING, FunctionDispatcher, choose_dir, choose_files, error_dialog,
-    gprefs, is_dark_theme, local_path_for_resource, question_dialog, safe_open_url,
+    NO_URL_FORMATTING,
+    FunctionDispatcher,
+    choose_dir,
+    choose_files,
+    error_dialog,
+    gprefs,
+    is_dark_theme,
+    local_path_for_resource,
+    question_dialog,
+    safe_open_url,
 )
 from calibre.gui2.book_details import resolved_css
 from calibre.gui2.dialogs.progress import ProgressDialog
diff --git a/src/calibre/gui2/complete2.py b/src/calibre/gui2/complete2.py
index 9e4c2b72b0..fb69d00741 100644
--- a/src/calibre/gui2/complete2.py
+++ b/src/calibre/gui2/complete2.py
@@ -6,14 +6,30 @@ __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from qt.core import (
-    QLineEdit, QAbstractListModel, Qt, pyqtSignal, QObject, QKeySequence, QAbstractItemView,
-    QApplication, QListView, QPoint, QModelIndex, QEvent, pyqtProperty,
-    QStyleOptionComboBox, QStyle, QComboBox, QTimer, sip)
+    QAbstractItemView,
+    QAbstractListModel,
+    QApplication,
+    QComboBox,
+    QEvent,
+    QKeySequence,
+    QLineEdit,
+    QListView,
+    QModelIndex,
+    QObject,
+    QPoint,
+    QStyle,
+    QStyleOptionComboBox,
+    Qt,
+    QTimer,
+    pyqtProperty,
+    pyqtSignal,
+    sip,
+)
 
 from calibre.constants import ismacos
-from calibre.utils.icu import sort_key, primary_startswith, primary_contains
 from calibre.gui2.widgets import EnComboBox, LineEditECM
 from calibre.utils.config import tweaks
+from calibre.utils.icu import primary_contains, primary_startswith, sort_key
 
 
 def containsq(x, prefix):
@@ -561,6 +577,7 @@ class EditWithComplete(EnComboBox):
 
 if __name__ == '__main__':
     from qt.core import QDialog, QVBoxLayout
+
     from calibre.gui2 import Application
     app = Application([])
     d = QDialog()
diff --git a/src/calibre/gui2/convert/__init__.py b/src/calibre/gui2/convert/__init__.py
index af085562ba..1194417ae2 100644
--- a/src/calibre/gui2/convert/__init__.py
+++ b/src/calibre/gui2/convert/__init__.py
@@ -5,18 +5,34 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import textwrap, codecs, importlib
+import codecs
+import importlib
+import textwrap
 from functools import partial
 
-from qt.core import (QWidget, QSpinBox, QDoubleSpinBox, QLineEdit, QTextEdit,
-    QCheckBox, QComboBox, Qt, QIcon, pyqtSignal, QLabel, QFontComboBox, QFont,
-    QFontInfo, QPlainTextEdit)
+from qt.core import (
+    QCheckBox,
+    QComboBox,
+    QDoubleSpinBox,
+    QFont,
+    QFontComboBox,
+    QFontInfo,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QPlainTextEdit,
+    QSpinBox,
+    Qt,
+    QTextEdit,
+    QWidget,
+    pyqtSignal,
+)
 
-from calibre.customize.conversion import OptionRecommendation
-from calibre.ebooks.conversion.config import (
-    load_defaults, save_defaults as save_defaults_, load_specifics, GuiRecommendations)
 from calibre import prepare_string_for_xml
+from calibre.customize.conversion import OptionRecommendation
 from calibre.customize.ui import plugin_for_input_format
+from calibre.ebooks.conversion.config import GuiRecommendations, load_defaults, load_specifics
+from calibre.ebooks.conversion.config import save_defaults as save_defaults_
 from calibre.gui2.font_family_chooser import FontFamilyChooser
 
 
@@ -138,8 +154,8 @@ class Widget(QWidget):
                 gui_opt.setDisabled(True)
 
     def get_value(self, g):
-        from calibre.gui2.convert.xpath_wizard import XPathEdit
         from calibre.gui2.convert.regex_builder import RegexEdit
+        from calibre.gui2.convert.xpath_wizard import XPathEdit
         from calibre.gui2.widgets import EncodingComboBox
         ret = self.get_value_handler(g)
         if ret != 'this is a dummy return value, xcswx1avcx4x':
@@ -190,8 +206,8 @@ class Widget(QWidget):
             return
         except NotImplementedError:
             pass
-        from calibre.gui2.convert.xpath_wizard import XPathEdit
         from calibre.gui2.convert.regex_builder import RegexEdit
+        from calibre.gui2.convert.xpath_wizard import XPathEdit
         if isinstance(g, (QSpinBox, QDoubleSpinBox)):
             g.valueChanged.connect(f)
         elif isinstance(g, (QLineEdit, QTextEdit, QPlainTextEdit)):
@@ -213,8 +229,8 @@ class Widget(QWidget):
         raise NotImplementedError()
 
     def set_value(self, g, val):
-        from calibre.gui2.convert.xpath_wizard import XPathEdit
         from calibre.gui2.convert.regex_builder import RegexEdit
+        from calibre.gui2.convert.xpath_wizard import XPathEdit
         from calibre.gui2.widgets import EncodingComboBox
         if self.set_value_handler(g, val):
             return
diff --git a/src/calibre/gui2/convert/azw3_output.py b/src/calibre/gui2/convert/azw3_output.py
index 5be642413f..a94937ae22 100644
--- a/src/calibre/gui2/convert/azw3_output.py
+++ b/src/calibre/gui2/convert/azw3_output.py
@@ -6,9 +6,9 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.convert.azw3_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.azw3_output_ui import Ui_Form
 
 font_family_model = None
 
diff --git a/src/calibre/gui2/convert/bulk.py b/src/calibre/gui2/convert/bulk.py
index cfd2c97405..e0e2034524 100644
--- a/src/calibre/gui2/convert/bulk.py
+++ b/src/calibre/gui2/convert/bulk.py
@@ -3,11 +3,10 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 import shutil
+
 from qt.core import QDialog, QDialogButtonBox, QModelIndex
 
-from calibre.ebooks.conversion.config import (
-    get_output_formats, sort_formats_by_preference,
-)
+from calibre.ebooks.conversion.config import get_output_formats, sort_formats_by_preference
 from calibre.ebooks.conversion.plumber import Plumber
 from calibre.gui2.convert import GuiRecommendations
 from calibre.gui2.convert.heuristics import HeuristicsWidget
diff --git a/src/calibre/gui2/convert/comic_input.py b/src/calibre/gui2/convert/comic_input.py
index 90c0c855e3..c8eb6bf93d 100644
--- a/src/calibre/gui2/convert/comic_input.py
+++ b/src/calibre/gui2/convert/comic_input.py
@@ -6,9 +6,9 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.convert.comic_input_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.comic_input_ui import Ui_Form
 
 
 class PluginWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/debug.py b/src/calibre/gui2/convert/debug.py
index e61e93bd2f..55f5e7fae9 100644
--- a/src/calibre/gui2/convert/debug.py
+++ b/src/calibre/gui2/convert/debug.py
@@ -7,10 +7,10 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.gui2.convert.debug_ui import Ui_Form
-from calibre.gui2.convert import Widget
-from calibre.gui2 import error_dialog, choose_dir
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2 import choose_dir, error_dialog
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.debug_ui import Ui_Form
 
 
 class DebugWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/docx_input.py b/src/calibre/gui2/convert/docx_input.py
index 4948e6fd47..b4c4c538bd 100644
--- a/src/calibre/gui2/convert/docx_input.py
+++ b/src/calibre/gui2/convert/docx_input.py
@@ -4,9 +4,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from calibre.gui2.convert.docx_input_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.docx_input_ui import Ui_Form
 
 
 class PluginWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/docx_output.py b/src/calibre/gui2/convert/docx_output.py
index 5440db5285..c0a839e13d 100644
--- a/src/calibre/gui2/convert/docx_output.py
+++ b/src/calibre/gui2/convert/docx_output.py
@@ -2,10 +2,10 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import QFormLayout, QComboBox, QCheckBox, QLineEdit, QDoubleSpinBox, QSizePolicy
+from qt.core import QCheckBox, QComboBox, QDoubleSpinBox, QFormLayout, QLineEdit, QSizePolicy
 
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
 
 paper_size_model = None
 orientation_model = None
diff --git a/src/calibre/gui2/convert/epub_output.py b/src/calibre/gui2/convert/epub_output.py
index a8b4e9b8c7..3c31b30f4a 100644
--- a/src/calibre/gui2/convert/epub_output.py
+++ b/src/calibre/gui2/convert/epub_output.py
@@ -6,9 +6,9 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.convert.epub_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.epub_output_ui import Ui_Form
 
 
 class PluginWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/fb2_input.py b/src/calibre/gui2/convert/fb2_input.py
index 409cf719ce..f4ae5cbd78 100644
--- a/src/calibre/gui2/convert/fb2_input.py
+++ b/src/calibre/gui2/convert/fb2_input.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.fb2_input_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.fb2_input_ui import Ui_Form
 
 
 class PluginWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/fb2_output.py b/src/calibre/gui2/convert/fb2_output.py
index c8011df491..496d0b55fa 100644
--- a/src/calibre/gui2/convert/fb2_output.py
+++ b/src/calibre/gui2/convert/fb2_output.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.fb2_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.fb2_output_ui import Ui_Form
 
 format_model = None
 
diff --git a/src/calibre/gui2/convert/gui_conversion.py b/src/calibre/gui2/convert/gui_conversion.py
index 2a1374df7b..641af19e33 100644
--- a/src/calibre/gui2/convert/gui_conversion.py
+++ b/src/calibre/gui2/convert/gui_conversion.py
@@ -5,9 +5,9 @@ __docformat__ = 'restructuredtext en'
 import os
 from optparse import OptionParser
 
-from calibre.customize.conversion import OptionRecommendation, DummyReporter
-from calibre.ebooks.conversion.plumber import Plumber
+from calibre.customize.conversion import DummyReporter, OptionRecommendation
 from calibre.customize.ui import plugin_for_catalog_format
+from calibre.ebooks.conversion.plumber import Plumber
 from calibre.utils.logging import Log
 
 
diff --git a/src/calibre/gui2/convert/heuristics.py b/src/calibre/gui2/convert/heuristics.py
index e60bc76b3a..50afe83314 100644
--- a/src/calibre/gui2/convert/heuristics.py
+++ b/src/calibre/gui2/convert/heuristics.py
@@ -4,11 +4,11 @@ __docformat__ = 'restructuredtext en'
 
 from qt.core import Qt
 
-from calibre.gui2 import gprefs
-from calibre.gui2.convert.heuristics_ui import Ui_Form
-from calibre.gui2.convert import Widget
-from calibre.utils.localization import localize_user_manual_link
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2 import gprefs
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.heuristics_ui import Ui_Form
+from calibre.utils.localization import localize_user_manual_link
 
 
 class HeuristicsWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/htmlz_output.py b/src/calibre/gui2/convert/htmlz_output.py
index 73f1e0e9cf..998fe8048b 100644
--- a/src/calibre/gui2/convert/htmlz_output.py
+++ b/src/calibre/gui2/convert/htmlz_output.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.htmlz_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.htmlz_output_ui import Ui_Form
 
 format_model = None
 
diff --git a/src/calibre/gui2/convert/look_and_feel.py b/src/calibre/gui2/convert/look_and_feel.py
index a3ea165681..deb7a7194e 100644
--- a/src/calibre/gui2/convert/look_and_feel.py
+++ b/src/calibre/gui2/convert/look_and_feel.py
@@ -6,6 +6,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import json
+
 from qt.core import QDialog, Qt
 
 from calibre.ebooks.conversion.config import OPTIONS
diff --git a/src/calibre/gui2/convert/lrf_output.py b/src/calibre/gui2/convert/lrf_output.py
index c1a48f0a22..7ecb1aaf62 100644
--- a/src/calibre/gui2/convert/lrf_output.py
+++ b/src/calibre/gui2/convert/lrf_output.py
@@ -5,9 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.lrf_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.lrf_output_ui import Ui_Form
 
 font_family_model = None
 
diff --git a/src/calibre/gui2/convert/metadata.py b/src/calibre/gui2/convert/metadata.py
index dd7caf624f..a6f587f255 100644
--- a/src/calibre/gui2/convert/metadata.py
+++ b/src/calibre/gui2/convert/metadata.py
@@ -5,21 +5,21 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, re
+import os
+import re
 
-from qt.core import QPixmap, QApplication
+from qt.core import QApplication, QPixmap
 
-from calibre.gui2 import choose_images, error_dialog
-from calibre.gui2.convert.metadata_ui import Ui_Form
-from calibre.ebooks.metadata import (string_to_authors, MetaInformation,
-        title_sort)
-from calibre.ebooks.metadata.opf2 import metadata_to_opf
-from calibre.ptempfile import PersistentTemporaryFile
-from calibre.gui2.convert import Widget
-from calibre.utils.icu import sort_key
-from calibre.library.comments import comments_to_html
-from calibre.utils.config import tweaks
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.ebooks.metadata import MetaInformation, string_to_authors, title_sort
+from calibre.ebooks.metadata.opf2 import metadata_to_opf
+from calibre.gui2 import choose_images, error_dialog
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.metadata_ui import Ui_Form
+from calibre.library.comments import comments_to_html
+from calibre.ptempfile import PersistentTemporaryFile
+from calibre.utils.config import tweaks
+from calibre.utils.icu import sort_key
 
 
 def create_opf_file(db, book_id, opf_file=None):
diff --git a/src/calibre/gui2/convert/mobi_output.py b/src/calibre/gui2/convert/mobi_output.py
index 9f14301b3d..cd97aa4c81 100644
--- a/src/calibre/gui2/convert/mobi_output.py
+++ b/src/calibre/gui2/convert/mobi_output.py
@@ -6,9 +6,9 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.convert.mobi_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.mobi_output_ui import Ui_Form
 
 font_family_model = None
 
diff --git a/src/calibre/gui2/convert/page_setup.py b/src/calibre/gui2/convert/page_setup.py
index 4a89bb02b7..4d0e94181f 100644
--- a/src/calibre/gui2/convert/page_setup.py
+++ b/src/calibre/gui2/convert/page_setup.py
@@ -5,12 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import Qt, QAbstractListModel, QModelIndex, QItemSelectionModel
+from qt.core import QAbstractListModel, QItemSelectionModel, QModelIndex, Qt
 
-from calibre.gui2.convert.page_setup_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.customize.ui import input_profiles, output_profiles
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.page_setup_ui import Ui_Form
 
 
 class ProfileModel(QAbstractListModel):
diff --git a/src/calibre/gui2/convert/pdb_output.py b/src/calibre/gui2/convert/pdb_output.py
index 4c1fd0c71d..05508593f2 100644
--- a/src/calibre/gui2/convert/pdb_output.py
+++ b/src/calibre/gui2/convert/pdb_output.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.pdb_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.pdb_output_ui import Ui_Form
 
 format_model = None
 
diff --git a/src/calibre/gui2/convert/pdf_input.py b/src/calibre/gui2/convert/pdf_input.py
index 57b76e270d..9c6f952de6 100644
--- a/src/calibre/gui2/convert/pdf_input.py
+++ b/src/calibre/gui2/convert/pdf_input.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.pdf_input_ui import Ui_Form
-from calibre.gui2.convert import Widget, QDoubleSpinBox
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import QDoubleSpinBox, Widget
+from calibre.gui2.convert.pdf_input_ui import Ui_Form
 
 
 class PluginWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/pdf_output.py b/src/calibre/gui2/convert/pdf_output.py
index 1dd0e6aabc..664f8ac986 100644
--- a/src/calibre/gui2/convert/pdf_output.py
+++ b/src/calibre/gui2/convert/pdf_output.py
@@ -3,12 +3,12 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import QHBoxLayout, QFormLayout, QDoubleSpinBox, QCheckBox, QVBoxLayout
+from qt.core import QCheckBox, QDoubleSpinBox, QFormLayout, QHBoxLayout, QVBoxLayout
 
-from calibre.gui2.convert.pdf_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
-from calibre.utils.localization import localize_user_manual_link
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.pdf_output_ui import Ui_Form
+from calibre.utils.localization import localize_user_manual_link
 
 paper_size_model = None
 orientation_model = None
diff --git a/src/calibre/gui2/convert/pml_output.py b/src/calibre/gui2/convert/pml_output.py
index 00d66ad224..9a48084142 100644
--- a/src/calibre/gui2/convert/pml_output.py
+++ b/src/calibre/gui2/convert/pml_output.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.pmlz_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.pmlz_output_ui import Ui_Form
 
 format_model = None
 
diff --git a/src/calibre/gui2/convert/rb_output.py b/src/calibre/gui2/convert/rb_output.py
index 09777b4bcd..41a5b01893 100644
--- a/src/calibre/gui2/convert/rb_output.py
+++ b/src/calibre/gui2/convert/rb_output.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.rb_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.rb_output_ui import Ui_Form
 
 format_model = None
 
diff --git a/src/calibre/gui2/convert/regex_builder.py b/src/calibre/gui2/convert/regex_builder.py
index bdf8136b35..3057e6ed4d 100644
--- a/src/calibre/gui2/convert/regex_builder.py
+++ b/src/calibre/gui2/convert/regex_builder.py
@@ -3,9 +3,8 @@
 
 import os
 from contextlib import suppress
-from qt.core import (
-    QBrush, QDialog, QDialogButtonBox, Qt, QTextCursor, QTextEdit, pyqtSignal,
-)
+
+from qt.core import QBrush, QDialog, QDialogButtonBox, Qt, QTextCursor, QTextEdit, pyqtSignal
 
 from calibre.constants import iswindows
 from calibre.ebooks.conversion.search_replace import compile_regular_expression
diff --git a/src/calibre/gui2/convert/rtf_input.py b/src/calibre/gui2/convert/rtf_input.py
index 365016fa84..ebf7b4a1a0 100644
--- a/src/calibre/gui2/convert/rtf_input.py
+++ b/src/calibre/gui2/convert/rtf_input.py
@@ -4,9 +4,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from calibre.gui2.convert.rtf_input_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.rtf_input_ui import Ui_Form
 
 
 class PluginWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/search_and_replace.py b/src/calibre/gui2/convert/search_and_replace.py
index 587268d41a..1eabfc756b 100644
--- a/src/calibre/gui2/convert/search_and_replace.py
+++ b/src/calibre/gui2/convert/search_and_replace.py
@@ -2,18 +2,18 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>, 2012 Eli Algranti <idea00@hotmail.com>'
 __docformat__ = 'restructuredtext en'
 
-import codecs, json
+import codecs
+import json
 
 from qt.core import Qt, QTableWidgetItem
 
-from calibre.gui2.convert.search_and_replace_ui import Ui_Form
-from calibre.gui2.convert import Widget
-from calibre.gui2 import (error_dialog, question_dialog, choose_files,
-        choose_save_file)
 from calibre import as_unicode
-from calibre.utils.localization import localize_user_manual_link
-from calibre.ebooks.conversion.search_replace import compile_regular_expression
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.ebooks.conversion.search_replace import compile_regular_expression
+from calibre.gui2 import choose_files, choose_save_file, error_dialog, question_dialog
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.search_and_replace_ui import Ui_Form
+from calibre.utils.localization import localize_user_manual_link
 
 
 class SearchAndReplaceWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/single.py b/src/calibre/gui2/convert/single.py
index 7a65bfd286..8587ba95bd 100644
--- a/src/calibre/gui2/convert/single.py
+++ b/src/calibre/gui2/convert/single.py
@@ -5,16 +5,36 @@
 import shutil
 
 from qt.core import (
-    QAbstractListModel, QCheckBox, QComboBox, QDialog,
-    QDialogButtonBox, QFont, QFrame, QGridLayout, QHBoxLayout, QIcon, QLabel,
-    QListView, QModelIndex, QScrollArea, QSize, QSizePolicy, QSpacerItem,
-    Qt, QTextEdit, QWidget
+    QAbstractListModel,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFrame,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QListView,
+    QModelIndex,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QSpacerItem,
+    Qt,
+    QTextEdit,
+    QWidget,
 )
 
 from calibre.customize.conversion import OptionRecommendation
 from calibre.ebooks.conversion.config import (
-    GuiRecommendations, delete_specifics, get_input_format_for_book,
-    get_output_formats, save_specifics, sort_formats_by_preference
+    GuiRecommendations,
+    delete_specifics,
+    get_input_format_for_book,
+    get_output_formats,
+    save_specifics,
+    sort_formats_by_preference,
 )
 from calibre.ebooks.conversion.plumber import create_dummy_plumber
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/convert/snb_output.py b/src/calibre/gui2/convert/snb_output.py
index 5baf0b9418..1c4a211903 100644
--- a/src/calibre/gui2/convert/snb_output.py
+++ b/src/calibre/gui2/convert/snb_output.py
@@ -2,9 +2,9 @@ __license__ = 'GPL 3'
 __copyright__ = '2010, Li Fanxi <lifanxi@freemindworld.com>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.snb_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.snb_output_ui import Ui_Form
 
 newline_model = None
 
diff --git a/src/calibre/gui2/convert/structure_detection.py b/src/calibre/gui2/convert/structure_detection.py
index 56a1901fe4..81a54e4c95 100644
--- a/src/calibre/gui2/convert/structure_detection.py
+++ b/src/calibre/gui2/convert/structure_detection.py
@@ -5,10 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.gui2.convert.structure_detection_ui import Ui_Form
-from calibre.gui2.convert import Widget
-from calibre.gui2 import error_dialog
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2 import error_dialog
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.structure_detection_ui import Ui_Form
 
 
 class StructureDetectionWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/toc.py b/src/calibre/gui2/convert/toc.py
index 719f6b9d02..95ab6c597c 100644
--- a/src/calibre/gui2/convert/toc.py
+++ b/src/calibre/gui2/convert/toc.py
@@ -6,11 +6,11 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.convert.toc_ui import Ui_Form
-from calibre.gui2.convert import Widget
-from calibre.gui2 import error_dialog
-from calibre.utils.localization import localize_user_manual_link
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2 import error_dialog
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.toc_ui import Ui_Form
+from calibre.utils.localization import localize_user_manual_link
 
 
 class TOCWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/txt_input.py b/src/calibre/gui2/convert/txt_input.py
index fcbf3f3fe4..dcd9591bd9 100644
--- a/src/calibre/gui2/convert/txt_input.py
+++ b/src/calibre/gui2/convert/txt_input.py
@@ -4,10 +4,10 @@ __docformat__ = 'restructuredtext en'
 
 from qt.core import QListWidgetItem, Qt
 
-from calibre.gui2.convert.txt_input_ui import Ui_Form
-from calibre.gui2.convert import Widget
-from calibre.ebooks.conversion.plugins.txt_input import MD_EXTENSIONS
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.ebooks.conversion.plugins.txt_input import MD_EXTENSIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.txt_input_ui import Ui_Form
 from polyglot.builtins import iteritems, itervalues
 
 
diff --git a/src/calibre/gui2/convert/txt_output.py b/src/calibre/gui2/convert/txt_output.py
index afca70c9d0..32add1ece6 100644
--- a/src/calibre/gui2/convert/txt_output.py
+++ b/src/calibre/gui2/convert/txt_output.py
@@ -3,9 +3,9 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.convert.txt_output_ui import Ui_Form
-from calibre.gui2.convert import Widget
 from calibre.ebooks.conversion.config import OPTIONS
+from calibre.gui2.convert import Widget
+from calibre.gui2.convert.txt_output_ui import Ui_Form
 
 
 class PluginWidget(Widget, Ui_Form):
diff --git a/src/calibre/gui2/convert/xpath_wizard.py b/src/calibre/gui2/convert/xpath_wizard.py
index 4d5f964ac8..3a713ac578 100644
--- a/src/calibre/gui2/convert/xpath_wizard.py
+++ b/src/calibre/gui2/convert/xpath_wizard.py
@@ -5,10 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import (
-    QComboBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QSize, Qt,
-    QToolButton, QVBoxLayout, QWidget
-)
+from qt.core import QComboBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QSize, Qt, QToolButton, QVBoxLayout, QWidget
 
 from calibre.gui2.convert.xpath_wizard_ui import Ui_Form
 from calibre.gui2.widgets import HistoryLineEdit
diff --git a/src/calibre/gui2/cover_flow.py b/src/calibre/gui2/cover_flow.py
index 7be538f4bf..7fd9a6d04a 100644
--- a/src/calibre/gui2/cover_flow.py
+++ b/src/calibre/gui2/cover_flow.py
@@ -12,9 +12,22 @@ Module to implement the Cover Flow feature
 import os
 import sys
 import time
+
 from qt.core import (
-    QAction, QApplication, QDialog, QFont, QImage, QItemSelectionModel, QKeySequence,
-    QLabel, QSize, QSizePolicy, QStackedLayout, Qt, QTimer, pyqtSignal,
+    QAction,
+    QApplication,
+    QDialog,
+    QFont,
+    QImage,
+    QItemSelectionModel,
+    QKeySequence,
+    QLabel,
+    QSize,
+    QSizePolicy,
+    QStackedLayout,
+    Qt,
+    QTimer,
+    pyqtSignal,
 )
 
 from calibre.constants import islinux
diff --git a/src/calibre/gui2/covers.py b/src/calibre/gui2/covers.py
index 7dbb2ccabb..2db143e4d0 100644
--- a/src/calibre/gui2/covers.py
+++ b/src/calibre/gui2/covers.py
@@ -5,17 +5,40 @@ import os
 from collections import OrderedDict
 from contextlib import suppress
 from copy import deepcopy
+
 from qt.core import (
-    QCheckBox, QColor, QColorDialog, QDialog, QDialogButtonBox, QFormLayout, QFrame,
-    QGridLayout, QHBoxLayout, QIcon, QInputDialog, QLabel, QLineEdit, QListWidget,
-    QListWidgetItem, QMenu, QPixmap, QPushButton, QSize, QSizePolicy, QSpinBox, Qt,
-    QTabWidget, QTimer, QToolButton, QVBoxLayout, QWidget, pyqtSignal,
+    QCheckBox,
+    QColor,
+    QColorDialog,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QFrame,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QPixmap,
+    QPushButton,
+    QSize,
+    QSizePolicy,
+    QSpinBox,
+    Qt,
+    QTabWidget,
+    QTimer,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.constants import config_dir
-from calibre.ebooks.covers import (
-    all_styles, cprefs, default_color_themes, generate_cover, override_prefs,
-)
+from calibre.ebooks.covers import all_styles, cprefs, default_color_themes, generate_cover, override_prefs
 from calibre.gui2 import error_dialog, gprefs
 from calibre.gui2.font_family_chooser import FontFamilyChooser
 from calibre.startup import connect_lambda
diff --git a/src/calibre/gui2/css_transform_rules.py b/src/calibre/gui2/css_transform_rules.py
index 3468c70a6a..6c23f031d1 100644
--- a/src/calibre/gui2/css_transform_rules.py
+++ b/src/calibre/gui2/css_transform_rules.py
@@ -2,17 +2,25 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QWidget, QVBoxLayout, QHBoxLayout, QLabel, QComboBox, QLineEdit,
-    QPushButton, QSize, pyqtSignal, QMenu, QDialogButtonBox, QTextCursor
-)
+from qt.core import QComboBox, QDialogButtonBox, QHBoxLayout, QLabel, QLineEdit, QMenu, QPushButton, QSize, QTextCursor, QVBoxLayout, QWidget, pyqtSignal
 
 from calibre.ebooks.css_transform_rules import (
-    validate_rule, safe_parser, compile_rules, transform_sheet, ACTION_MAP, MATCH_TYPE_MAP, export_rules, import_rules)
-from calibre.gui2 import error_dialog, elided_text, choose_save_file, choose_files
-from calibre.gui2.tag_mapper import (
-    RuleEdit as RE, RuleEditDialog as RuleEditDialogBase, Rules as RulesBase,
-    RulesDialog as RulesDialogBase, RuleItem as RuleItemBase, SaveLoadMixin)
+    ACTION_MAP,
+    MATCH_TYPE_MAP,
+    compile_rules,
+    export_rules,
+    import_rules,
+    safe_parser,
+    transform_sheet,
+    validate_rule,
+)
+from calibre.gui2 import choose_files, choose_save_file, elided_text, error_dialog
+from calibre.gui2.tag_mapper import RuleEdit as RE
+from calibre.gui2.tag_mapper import RuleEditDialog as RuleEditDialogBase
+from calibre.gui2.tag_mapper import RuleItem as RuleItemBase
+from calibre.gui2.tag_mapper import Rules as RulesBase
+from calibre.gui2.tag_mapper import RulesDialog as RulesDialogBase
+from calibre.gui2.tag_mapper import SaveLoadMixin
 from calibre.gui2.widgets2 import Dialog
 from calibre.utils.config import JSONConfig
 from calibre.utils.localization import localize_user_manual_link
diff --git a/src/calibre/gui2/custom_column_widgets.py b/src/calibre/gui2/custom_column_widgets.py
index 2a8203827a..b29e932965 100644
--- a/src/calibre/gui2/custom_column_widgets.py
+++ b/src/calibre/gui2/custom_column_widgets.py
@@ -8,10 +8,29 @@ __docformat__ = 'restructuredtext en'
 import os
 from collections import OrderedDict
 from functools import partial
+
 from qt.core import (
-    QApplication, QCheckBox, QComboBox, QDialog, QDoubleSpinBox, QGridLayout,
-    QGroupBox, QHBoxLayout, QIcon, QLabel, QLineEdit, QMessageBox, QPlainTextEdit,
-    QSizePolicy, QSpacerItem, QSpinBox, QStyle, Qt, QToolButton, QUrl, QVBoxLayout,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDoubleSpinBox,
+    QGridLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QMessageBox,
+    QPlainTextEdit,
+    QSizePolicy,
+    QSpacerItem,
+    QSpinBox,
+    QStyle,
+    Qt,
+    QToolButton,
+    QUrl,
+    QVBoxLayout,
     QWidget,
 )
 
@@ -22,14 +41,13 @@ from calibre.gui2.complete2 import EditWithComplete as EWC
 from calibre.gui2.dialogs.tag_editor import TagEditor
 from calibre.gui2.library.delegates import ClearingDoubleSpinBox, ClearingSpinBox
 from calibre.gui2.markdown_editor import Editor as MarkdownEditor
-from calibre.gui2.widgets2 import DateTimeEdit as DateTimeEditBase, RatingEditor
+from calibre.gui2.widgets2 import DateTimeEdit as DateTimeEditBase
+from calibre.gui2.widgets2 import RatingEditor
 from calibre.library.comments import comments_to_html
 from calibre.utils.config import tweaks
-from calibre.utils.date import (
-    as_local_time, as_utc, internal_iso_format_string, is_date_undefined, now,
-    qt_from_dt, qt_to_dt,
-)
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.date import as_local_time, as_utc, internal_iso_format_string, is_date_undefined, now, qt_from_dt, qt_to_dt
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 
 
 class EditWithComplete(EWC):
diff --git a/src/calibre/gui2/device.py b/src/calibre/gui2/device.py
index 8b295da09a..1c00b1ac9d 100644
--- a/src/calibre/gui2/device.py
+++ b/src/calibre/gui2/device.py
@@ -10,23 +10,22 @@ import sys
 import time
 import traceback
 import weakref
-from qt.core import (
-    QAction, QActionGroup, QCoreApplication, QDialog, QDialogButtonBox, QEventLoop,
-    QIcon, QMenu, QObject, QTimer, QVBoxLayout, pyqtSignal,
-)
 from threading import Event, Thread
 
-from calibre import (
-    as_unicode, force_unicode, preferred_encoding, prints, sanitize_file_name,
-)
+from qt.core import QAction, QActionGroup, QCoreApplication, QDialog, QDialogButtonBox, QEventLoop, QIcon, QMenu, QObject, QTimer, QVBoxLayout, pyqtSignal
+
+from calibre import as_unicode, force_unicode, preferred_encoding, prints, sanitize_file_name
 from calibre.constants import DEBUG
-from calibre.customize.ui import (
-    available_input_formats, available_output_formats, device_plugins,
-    disabled_device_plugins,
-)
+from calibre.customize.ui import available_input_formats, available_output_formats, device_plugins, disabled_device_plugins
 from calibre.devices.errors import (
-    BlacklistedDevice, FreeSpaceError, InitialConnectionError, OpenActionNeeded,
-    OpenFailed, OpenFeedback, UserFeedback, WrongDestinationError,
+    BlacklistedDevice,
+    FreeSpaceError,
+    InitialConnectionError,
+    OpenActionNeeded,
+    OpenFailed,
+    OpenFeedback,
+    UserFeedback,
+    WrongDestinationError,
 )
 from calibre.devices.folder_device.driver import FOLDER_DEVICE
 from calibre.devices.interface import DevicePlugin, currently_connected_device
@@ -34,15 +33,23 @@ from calibre.devices.scanner import DeviceScanner
 from calibre.ebooks.covers import cprefs, generate_cover, override_prefs, scale_cover
 from calibre.ebooks.metadata import authors_to_string
 from calibre.gui2 import (
-    Dispatcher, FunctionDispatcher, choose_dir, config, dynamic, error_dialog, gprefs,
-    info_dialog, question_dialog, show_restart_warning, warning_dialog,
+    Dispatcher,
+    FunctionDispatcher,
+    choose_dir,
+    config,
+    dynamic,
+    error_dialog,
+    gprefs,
+    info_dialog,
+    question_dialog,
+    show_restart_warning,
+    warning_dialog,
 )
 from calibre.gui2.dialogs.choose_format_device import ChooseFormatDeviceDialog
 from calibre.gui2.widgets import BusyCursor
 from calibre.library.save_to_disk import find_plugboard
-from calibre.ptempfile import (
-    PersistentTemporaryFile, force_unicode as filename_to_unicode,
-)
+from calibre.ptempfile import PersistentTemporaryFile
+from calibre.ptempfile import force_unicode as filename_to_unicode
 from calibre.startup import connect_lambda
 from calibre.utils.config import device_prefs, tweaks
 from calibre.utils.filenames import ascii_filename
diff --git a/src/calibre/gui2/device_drivers/configwidget.py b/src/calibre/gui2/device_drivers/configwidget.py
index 6bad19f38c..2f15914533 100644
--- a/src/calibre/gui2/device_drivers/configwidget.py
+++ b/src/calibre/gui2/device_drivers/configwidget.py
@@ -4,13 +4,12 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from qt.core import (QWidget, QListWidgetItem, Qt, QLabel,
-        QLineEdit, QCheckBox, QComboBox)
+from qt.core import QCheckBox, QComboBox, QLabel, QLineEdit, QListWidgetItem, Qt, QWidget
 
+from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.gui2 import error_dialog, question_dialog
 from calibre.gui2.device_drivers.configwidget_ui import Ui_ConfigWidget
 from calibre.utils.formatter import validation_formatter
-from calibre.ebooks import BOOK_EXTENSIONS
 
 
 class ConfigWidget(QWidget, Ui_ConfigWidget):
diff --git a/src/calibre/gui2/device_drivers/mtp_config.py b/src/calibre/gui2/device_drivers/mtp_config.py
index f562a59c33..4c45121e37 100644
--- a/src/calibre/gui2/device_drivers/mtp_config.py
+++ b/src/calibre/gui2/device_drivers/mtp_config.py
@@ -7,17 +7,37 @@ __docformat__ = 'restructuredtext en'
 
 import weakref
 
-from qt.core import (QWidget, QListWidgetItem, Qt, QToolButton, QLabel,
-        QTabWidget, QGridLayout, QListWidget, QIcon, QLineEdit, QVBoxLayout,
-        QPushButton, QGroupBox, QScrollArea, QHBoxLayout, QComboBox,
-        pyqtSignal, QSizePolicy, QDialog, QDialogButtonBox, QPlainTextEdit,
-        QApplication, QSize)
+from qt.core import (
+    QApplication,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QPlainTextEdit,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    Qt,
+    QTabWidget,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
 
 from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.gui2 import error_dialog
+from calibre.gui2.device_drivers.mtp_folder_browser import Browser, IgnoredFolders
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
 from calibre.utils.date import parse_date
-from calibre.gui2.device_drivers.mtp_folder_browser import Browser, IgnoredFolders
 from polyglot.builtins import iteritems
 
 
@@ -527,9 +547,9 @@ class SendError(QDialog):
 
 
 if __name__ == '__main__':
-    from calibre.gui2 import Application
     from calibre.devices.mtp.driver import MTP_DEVICE
     from calibre.devices.scanner import DeviceScanner
+    from calibre.gui2 import Application
     s = DeviceScanner()
     s.scan()
     app = Application([])
diff --git a/src/calibre/gui2/device_drivers/mtp_folder_browser.py b/src/calibre/gui2/device_drivers/mtp_folder_browser.py
index a852b6b83e..d283587bf9 100644
--- a/src/calibre/gui2/device_drivers/mtp_folder_browser.py
+++ b/src/calibre/gui2/device_drivers/mtp_folder_browser.py
@@ -6,10 +6,8 @@ __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from operator import attrgetter
-from qt.core import (
-    QDialog, QDialogButtonBox, QIcon, QLabel, QSize, Qt, QTabWidget, QTreeWidget,
-    QTreeWidgetItem, QVBoxLayout, pyqtSignal,
-)
+
+from qt.core import QDialog, QDialogButtonBox, QIcon, QLabel, QSize, Qt, QTabWidget, QTreeWidget, QTreeWidgetItem, QVBoxLayout, pyqtSignal
 
 from calibre.gui2 import file_icon_provider
 from calibre.utils.icu import lower as icu_lower
diff --git a/src/calibre/gui2/device_drivers/tabbed_device_config.py b/src/calibre/gui2/device_drivers/tabbed_device_config.py
index 5e3789ee3b..783bb695fa 100644
--- a/src/calibre/gui2/device_drivers/tabbed_device_config.py
+++ b/src/calibre/gui2/device_drivers/tabbed_device_config.py
@@ -4,16 +4,28 @@ __license__   = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import weakref, textwrap
+import textwrap
+import weakref
 
 from qt.core import (
-    QWidget, QLabel, QTabWidget, QGridLayout, QLineEdit, QVBoxLayout,
-    QGroupBox, QComboBox, QSizePolicy, QDialog, QDialogButtonBox, QCheckBox,
-    QSpacerItem)
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QGroupBox,
+    QLabel,
+    QLineEdit,
+    QSizePolicy,
+    QSpacerItem,
+    QTabWidget,
+    QVBoxLayout,
+    QWidget,
+)
 
-from calibre.ebooks import BOOK_EXTENSIONS
-from calibre.gui2.device_drivers.mtp_config import (FormatsConfig, TemplateConfig)
 from calibre.devices.usbms.driver import debug_print
+from calibre.ebooks import BOOK_EXTENSIONS
+from calibre.gui2.device_drivers.mtp_config import FormatsConfig, TemplateConfig
 
 
 def wrap_msg(msg):
@@ -372,9 +384,9 @@ class DeviceOptionsGroupBox(QGroupBox):
 
 
 if __name__ == '__main__':
-    from calibre.gui2 import Application
     from calibre.devices.kobo.driver import KOBO
     from calibre.devices.scanner import DeviceScanner
+    from calibre.gui2 import Application
     s = DeviceScanner()
     s.scan()
     app = Application([])
diff --git a/src/calibre/gui2/dialogs/add_empty_book.py b/src/calibre/gui2/dialogs/add_empty_book.py
index 17b395a136..c8772e44c2 100644
--- a/src/calibre/gui2/dialogs/add_empty_book.py
+++ b/src/calibre/gui2/dialogs/add_empty_book.py
@@ -6,13 +6,12 @@ __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
 
-from qt.core import (
-    QDialog, QGridLayout, QLabel, QDialogButtonBox,  QApplication, QSpinBox,
-    QToolButton, QIcon, QLineEdit, QComboBox, QCheckBox)
+from qt.core import QApplication, QCheckBox, QComboBox, QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QLineEdit, QSpinBox, QToolButton
+
 from calibre.ebooks.metadata import string_to_authors
+from calibre.gui2 import gprefs
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.utils.config import tweaks
-from calibre.gui2 import gprefs
 
 
 class AddEmptyBookDialog(QDialog):
diff --git a/src/calibre/gui2/dialogs/add_from_isbn.py b/src/calibre/gui2/dialogs/add_from_isbn.py
index 83302f326a..6d914a3bbc 100644
--- a/src/calibre/gui2/dialogs/add_from_isbn.py
+++ b/src/calibre/gui2/dialogs/add_from_isbn.py
@@ -6,10 +6,8 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import os
-from qt.core import (
-    QApplication, QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel,
-    QLineEdit, QPlainTextEdit, QPushButton, Qt, QVBoxLayout
-)
+
+from qt.core import QApplication, QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QLineEdit, QPlainTextEdit, QPushButton, Qt, QVBoxLayout
 
 from calibre.constants import iswindows
 from calibre.ebooks.metadata import check_isbn
diff --git a/src/calibre/gui2/dialogs/authors_edit.py b/src/calibre/gui2/dialogs/authors_edit.py
index d93aad884e..f0de795193 100644
--- a/src/calibre/gui2/dialogs/authors_edit.py
+++ b/src/calibre/gui2/dialogs/authors_edit.py
@@ -5,9 +5,21 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import OrderedDict
+
 from qt.core import (
-    QAbstractItemView, QApplication, QDialog, QDialogButtonBox, QGridLayout, QIcon,
-    QLabel, QListWidget, QPushButton, QSize, QStyledItemDelegate, Qt, pyqtSignal,
+    QAbstractItemView,
+    QApplication,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QIcon,
+    QLabel,
+    QListWidget,
+    QPushButton,
+    QSize,
+    QStyledItemDelegate,
+    Qt,
+    pyqtSignal,
 )
 
 from calibre.ebooks.metadata import string_to_authors
diff --git a/src/calibre/gui2/dialogs/book_info.py b/src/calibre/gui2/dialogs/book_info.py
index e35fb71646..309c92b8bd 100644
--- a/src/calibre/gui2/dialogs/book_info.py
+++ b/src/calibre/gui2/dialogs/book_info.py
@@ -6,19 +6,37 @@ import textwrap
 from enum import IntEnum
 
 from qt.core import (
-    QAction, QApplication, QBrush, QCheckBox, QDialog, QDialogButtonBox, QGridLayout,
-    QHBoxLayout, QIcon, QKeySequence, QLabel, QListView, QModelIndex, QPalette, QPixmap,
-    QPushButton, QShortcut, QSize, QSplitter, Qt, QTimer, QToolButton, QVBoxLayout,
-    QWidget, pyqtSignal,
+    QAction,
+    QApplication,
+    QBrush,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QListView,
+    QModelIndex,
+    QPalette,
+    QPixmap,
+    QPushButton,
+    QShortcut,
+    QSize,
+    QSplitter,
+    Qt,
+    QTimer,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import fit_image
 from calibre.db.constants import RESOURCE_URL_SCHEME
-from calibre.gui2 import NO_URL_FORMATTING, gprefs
-from calibre.gui2 import BOOK_DETAILS_DISPLAY_DEBOUNCE_DELAY
-from calibre.gui2.book_details import (
-    create_open_cover_with_menu, resolved_css, details_context_menu_event, render_html, set_html,
-)
+from calibre.gui2 import BOOK_DETAILS_DISPLAY_DEBOUNCE_DELAY, NO_URL_FORMATTING, gprefs
+from calibre.gui2.book_details import create_open_cover_with_menu, details_context_menu_event, render_html, resolved_css, set_html
 from calibre.gui2.ui import get_gui
 from calibre.gui2.widgets import CoverView
 from calibre.gui2.widgets2 import Dialog, HTMLDisplay
@@ -67,9 +85,7 @@ class Configure(Dialog):
         Dialog.__init__(self, _('Configure the Book details window'), 'book-details-popup-conf', parent)
 
     def setup_ui(self):
-        from calibre.gui2.preferences.look_feel import (
-            DisplayedFields, move_field_down, move_field_up,
-        )
+        from calibre.gui2.preferences.look_feel import DisplayedFields, move_field_down, move_field_up
         self.l = QVBoxLayout(self)
         self.field_display_order = fdo = QListView(self)
         self.model = DisplayedFields(self.db, fdo, pref_name='popup_book_display_fields')
diff --git a/src/calibre/gui2/dialogs/catalog.py b/src/calibre/gui2/dialogs/catalog.py
index a801c07f56..acc3b144ae 100644
--- a/src/calibre/gui2/dialogs/catalog.py
+++ b/src/calibre/gui2/dialogs/catalog.py
@@ -9,9 +9,8 @@ import importlib
 import os
 import sys
 import weakref
-from qt.core import (
-    QDialog, QDialogButtonBox, QScrollArea, QSize
-)
+
+from qt.core import QDialog, QDialogButtonBox, QScrollArea, QSize
 
 from calibre.customize import PluginInstallationType
 from calibre.customize.ui import catalog_plugins, config
@@ -25,6 +24,7 @@ class Catalog(QDialog, Ui_Dialog):
 
     def __init__(self, parent, dbspec, ids, db):
         import re
+
         from PyQt6.uic import compileUi
 
         from calibre import prints as info
diff --git a/src/calibre/gui2/dialogs/check_library.py b/src/calibre/gui2/dialogs/check_library.py
index 58e6c1268e..f36c37eed7 100644
--- a/src/calibre/gui2/dialogs/check_library.py
+++ b/src/calibre/gui2/dialogs/check_library.py
@@ -7,14 +7,33 @@ __license__   = 'GPL v3'
 
 import os
 import weakref
-from qt.core import (
-    QApplication, QCheckBox, QCursor, QDialog, QDialogButtonBox, QGridLayout,
-    QHBoxLayout, QIcon, QLabel, QLineEdit, QProgressBar, QPushButton,
-    QStackedLayout, Qt, QTextEdit, QTreeWidget, QTreeWidgetItem, QVBoxLayout,
-    QWidget, pyqtSignal, QSplitter, QToolButton
-)
 from threading import Thread
 
+from qt.core import (
+    QApplication,
+    QCheckBox,
+    QCursor,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QProgressBar,
+    QPushButton,
+    QSplitter,
+    QStackedLayout,
+    Qt,
+    QTextEdit,
+    QToolButton,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import as_unicode, prints
 from calibre.gui2 import open_local_file
 from calibre.gui2.dialogs.confirm_delete import confirm
diff --git a/src/calibre/gui2/dialogs/choose_format.py b/src/calibre/gui2/dialogs/choose_format.py
index 32b58034e7..fcf012141d 100644
--- a/src/calibre/gui2/dialogs/choose_format.py
+++ b/src/calibre/gui2/dialogs/choose_format.py
@@ -2,10 +2,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
-from qt.core import (
-    QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QListWidget, QListWidgetItem,
-    QMenu, QModelIndex, QPushButton, QSize, QVBoxLayout,
-)
+
+from qt.core import QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QListWidget, QListWidgetItem, QMenu, QModelIndex, QPushButton, QSize, QVBoxLayout
 
 from calibre.gui2 import file_icon_provider
 from calibre.startup import connect_lambda
diff --git a/src/calibre/gui2/dialogs/choose_format_device.py b/src/calibre/gui2/dialogs/choose_format_device.py
index 903b79813e..4fb26c02c4 100644
--- a/src/calibre/gui2/dialogs/choose_format_device.py
+++ b/src/calibre/gui2/dialogs/choose_format_device.py
@@ -1,7 +1,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 
-from qt.core import QDialog, QTreeWidgetItem, QIcon, QModelIndex
+from qt.core import QDialog, QIcon, QModelIndex, QTreeWidgetItem
 
 from calibre.gui2 import file_icon_provider
 from calibre.gui2.dialogs.choose_format_device_ui import Ui_ChooseFormatDeviceDialog
diff --git a/src/calibre/gui2/dialogs/choose_library.py b/src/calibre/gui2/dialogs/choose_library.py
index f03e1836c3..b5d1f49a6a 100644
--- a/src/calibre/gui2/dialogs/choose_library.py
+++ b/src/calibre/gui2/dialogs/choose_library.py
@@ -7,9 +7,10 @@ __docformat__ = 'restructuredtext en'
 
 import errno
 import os
-from qt.core import QDialog, Qt, QTimer, pyqtSignal
 from threading import Event, Thread
 
+from qt.core import QDialog, Qt, QTimer, pyqtSignal
+
 from calibre import force_unicode, isbytestring, patheq
 from calibre.constants import filesystem_encoding, get_portable_base, iswindows
 from calibre.gui2 import choose_dir, error_dialog
diff --git a/src/calibre/gui2/dialogs/choose_plugin_toolbars.py b/src/calibre/gui2/dialogs/choose_plugin_toolbars.py
index 710c5989ce..dc88345c16 100644
--- a/src/calibre/gui2/dialogs/choose_plugin_toolbars.py
+++ b/src/calibre/gui2/dialogs/choose_plugin_toolbars.py
@@ -6,8 +6,7 @@ __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
 
-from qt.core import (QDialog, QVBoxLayout, QLabel, QDialogButtonBox,
-            QListWidget, QAbstractItemView, QSizePolicy)
+from qt.core import QAbstractItemView, QDialog, QDialogButtonBox, QLabel, QListWidget, QSizePolicy, QVBoxLayout
 
 
 class ChoosePluginToolbarsDialog(QDialog):
diff --git a/src/calibre/gui2/dialogs/comments_dialog.py b/src/calibre/gui2/dialogs/comments_dialog.py
index 2768a38e5e..4747a918b9 100644
--- a/src/calibre/gui2/dialogs/comments_dialog.py
+++ b/src/calibre/gui2/dialogs/comments_dialog.py
@@ -5,10 +5,7 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
-from qt.core import (
-    QDialog, QDialogButtonBox, QHBoxLayout, QLabel, QPlainTextEdit, QSize, Qt,
-    QVBoxLayout, pyqtSignal,
-)
+from qt.core import QDialog, QDialogButtonBox, QHBoxLayout, QLabel, QPlainTextEdit, QSize, Qt, QVBoxLayout, pyqtSignal
 
 from calibre.gui2 import Application, gprefs
 from calibre.gui2.comments_editor import Editor
diff --git a/src/calibre/gui2/dialogs/confirm_delete.py b/src/calibre/gui2/dialogs/confirm_delete.py
index bf0209a881..d87fc7eb1a 100644
--- a/src/calibre/gui2/dialogs/confirm_delete.py
+++ b/src/calibre/gui2/dialogs/confirm_delete.py
@@ -5,9 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, Qt, QVBoxLayout,
-)
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, Qt, QVBoxLayout
 
 from calibre import confirm_config_name
 from calibre.gui2 import dynamic
diff --git a/src/calibre/gui2/dialogs/confirm_delete_location.py b/src/calibre/gui2/dialogs/confirm_delete_location.py
index acad8e9fb7..e7ba43446d 100644
--- a/src/calibre/gui2/dialogs/confirm_delete_location.py
+++ b/src/calibre/gui2/dialogs/confirm_delete_location.py
@@ -6,7 +6,7 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net' \
                 '2010, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import QDialog, QIcon, Qt, QVBoxLayout, QHBoxLayout, QSizePolicy, QLabel, QPushButton
+from qt.core import QDialog, QHBoxLayout, QIcon, QLabel, QPushButton, QSizePolicy, Qt, QVBoxLayout
 
 from calibre.startup import connect_lambda
 
diff --git a/src/calibre/gui2/dialogs/confirm_merge.py b/src/calibre/gui2/dialogs/confirm_merge.py
index 58e4c47a99..8b73037a94 100644
--- a/src/calibre/gui2/dialogs/confirm_merge.py
+++ b/src/calibre/gui2/dialogs/confirm_merge.py
@@ -6,10 +6,7 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from typing import NamedTuple
 
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QLabel, QSplitter, Qt, QTextBrowser,
-    QVBoxLayout, QWidget,
-)
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QLabel, QSplitter, Qt, QTextBrowser, QVBoxLayout, QWidget
 
 from calibre.ebooks.metadata import authors_to_string
 from calibre.ebooks.metadata.book.base import field_metadata
diff --git a/src/calibre/gui2/dialogs/custom_recipes.py b/src/calibre/gui2/dialogs/custom_recipes.py
index afca6b7470..091eeb8b3c 100644
--- a/src/calibre/gui2/dialogs/custom_recipes.py
+++ b/src/calibre/gui2/dialogs/custom_recipes.py
@@ -4,24 +4,48 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, re, textwrap, time
+import os
+import re
+import textwrap
+import time
 
 from qt.core import (
-    QVBoxLayout, QStackedWidget, QSize, QPushButton, QIcon, QWidget, QListView, QItemSelectionModel,
-    QHBoxLayout, QAbstractListModel, Qt, QLabel, QSizePolicy, pyqtSignal, QSortFilterProxyModel,
-    QFormLayout, QSpinBox, QLineEdit, QGroupBox, QListWidget, QListWidgetItem,
-    QToolButton, QTreeView, QDialog, QDialogButtonBox)
+    QAbstractListModel,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QItemSelectionModel,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QListWidget,
+    QListWidgetItem,
+    QPushButton,
+    QSize,
+    QSizePolicy,
+    QSortFilterProxyModel,
+    QSpinBox,
+    QStackedWidget,
+    Qt,
+    QToolButton,
+    QTreeView,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
 
-from calibre.gui2 import error_dialog, open_local_file, choose_files, choose_save_file
+from calibre.gui2 import choose_files, choose_save_file, error_dialog, open_local_file
 from calibre.gui2.dialogs.confirm_delete import confirm as confirm_delete
-from calibre.gui2.widgets2 import Dialog
-from calibre.web.feeds.recipes import custom_recipes, compile_recipe
-from calibre.gui2.tweak_book.editor.text import TextEdit
-from calibre.web.feeds.recipes.collection import get_builtin_recipe_by_id
-from calibre.utils.localization import localize_user_manual_link
-from polyglot.builtins import iteritems, as_unicode
 from calibre.gui2.search_box import SearchBox2
-from polyglot.builtins import as_bytes
+from calibre.gui2.tweak_book.editor.text import TextEdit
+from calibre.gui2.widgets2 import Dialog
+from calibre.utils.localization import localize_user_manual_link
+from calibre.web.feeds.recipes import compile_recipe, custom_recipes
+from calibre.web.feeds.recipes.collection import get_builtin_recipe_by_id
+from polyglot.builtins import as_bytes, as_unicode, iteritems
 
 
 def is_basic_recipe(src):
diff --git a/src/calibre/gui2/dialogs/data_files_manager.py b/src/calibre/gui2/dialogs/data_files_manager.py
index be6fbeef69..716d36a727 100644
--- a/src/calibre/gui2/dialogs/data_files_manager.py
+++ b/src/calibre/gui2/dialogs/data_files_manager.py
@@ -8,24 +8,40 @@ from contextlib import contextmanager
 from datetime import datetime
 from functools import partial
 from math import ceil
+
 from qt.core import (
-    QAbstractItemView, QAbstractListModel, QComboBox, QCursor, QDialogButtonBox,
-    QHBoxLayout, QIcon, QItemSelection, QItemSelectionModel, QLabel, QListView, QMenu,
-    QPushButton, QRect, QSize, QStyle, QStyledItemDelegate, Qt, QTextDocument, QTimer,
-    QVBoxLayout, pyqtSignal, sip, QDropEvent
+    QAbstractItemView,
+    QAbstractListModel,
+    QComboBox,
+    QCursor,
+    QDialogButtonBox,
+    QDropEvent,
+    QHBoxLayout,
+    QIcon,
+    QItemSelection,
+    QItemSelectionModel,
+    QLabel,
+    QListView,
+    QMenu,
+    QPushButton,
+    QRect,
+    QSize,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTextDocument,
+    QTimer,
+    QVBoxLayout,
+    pyqtSignal,
+    sip,
 )
 
 from calibre import human_readable, prepare_string_for_xml
 from calibre.constants import ismacos
 from calibre.db.constants import DATA_DIR_NAME, DATA_FILE_PATTERN
-from calibre.gui2 import (
-    choose_files, error_dialog, file_icon_provider, gprefs, open_local_file,
-    question_dialog,
-)
+from calibre.gui2 import choose_files, error_dialog, file_icon_provider, gprefs, open_local_file, question_dialog
 from calibre.gui2.dialogs.confirm_delete import confirm
-from calibre.gui2.open_with import (
-    choose_program, edit_programs, populate_menu, run_program,
-)
+from calibre.gui2.open_with import choose_program, edit_programs, populate_menu, run_program
 from calibre.gui2.widgets2 import Dialog
 from calibre.utils.icu import primary_sort_key
 from calibre.utils.recycle_bin import delete_file
diff --git a/src/calibre/gui2/dialogs/delete_matching_from_device.py b/src/calibre/gui2/dialogs/delete_matching_from_device.py
index 2a0cc07bd1..fdea0b7641 100644
--- a/src/calibre/gui2/dialogs/delete_matching_from_device.py
+++ b/src/calibre/gui2/dialogs/delete_matching_from_device.py
@@ -5,13 +5,11 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 __license__   = 'GPL v3'
 
-from qt.core import Qt, QDialog, QTableWidgetItem, QAbstractItemView
+from qt.core import QAbstractItemView, QDialog, Qt, QTableWidgetItem
 
 from calibre import strftime
-from calibre.ebooks.metadata import authors_to_string, authors_to_sort_string, \
-                                    title_sort
-from calibre.gui2.dialogs.delete_matching_from_device_ui import \
-                                            Ui_DeleteMatchingFromDeviceDialog
+from calibre.ebooks.metadata import authors_to_sort_string, authors_to_string, title_sort
+from calibre.gui2.dialogs.delete_matching_from_device_ui import Ui_DeleteMatchingFromDeviceDialog
 from calibre.utils.date import UNDEFINED_DATE
 
 
diff --git a/src/calibre/gui2/dialogs/device_category_editor.py b/src/calibre/gui2/dialogs/device_category_editor.py
index 54e547f167..2219c20d0b 100644
--- a/src/calibre/gui2/dialogs/device_category_editor.py
+++ b/src/calibre/gui2/dialogs/device_category_editor.py
@@ -1,10 +1,10 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from qt.core import Qt, QDialog, QListWidgetItem
+from qt.core import QDialog, QListWidgetItem, Qt
 
+from calibre.gui2 import error_dialog, question_dialog
 from calibre.gui2.dialogs.device_category_editor_ui import Ui_DeviceCategoryEditor
-from calibre.gui2 import question_dialog, error_dialog
 
 
 class ListWidgetItem(QListWidgetItem):
diff --git a/src/calibre/gui2/dialogs/duplicates.py b/src/calibre/gui2/dialogs/duplicates.py
index 74815ea069..8d47ffce9c 100644
--- a/src/calibre/gui2/dialogs/duplicates.py
+++ b/src/calibre/gui2/dialogs/duplicates.py
@@ -6,10 +6,8 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import os.path
-from qt.core import (
-    QApplication, QDialog, QDialogButtonBox, QFont, QGridLayout, QIcon, QLabel, Qt,
-    QTreeWidget, QTreeWidgetItem,
-)
+
+from qt.core import QApplication, QDialog, QDialogButtonBox, QFont, QGridLayout, QIcon, QLabel, Qt, QTreeWidget, QTreeWidgetItem
 
 from calibre.ebooks.metadata import authors_to_string
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/dialogs/edit_authors_dialog.py b/src/calibre/gui2/dialogs/edit_authors_dialog.py
index baf50de69f..74c5c60462 100644
--- a/src/calibre/gui2/dialogs/edit_authors_dialog.py
+++ b/src/calibre/gui2/dialogs/edit_authors_dialog.py
@@ -7,21 +7,32 @@ __license__   = 'GPL v3'
 
 from contextlib import contextmanager
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QAction, QApplication, QDialog, QDialogButtonBox, QFrame,
-    QIcon, QLabel, QMenu, QStyledItemDelegate, Qt, QTableWidgetItem, QTimer,
+    QAbstractItemView,
+    QAction,
+    QApplication,
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QIcon,
+    QLabel,
+    QMenu,
+    QStyledItemDelegate,
+    Qt,
+    QTableWidgetItem,
+    QTimer,
 )
 
 from calibre.ebooks.metadata import author_to_author_sort, string_to_authors
 from calibre.gui2 import error_dialog, gprefs
 from calibre.gui2.dialogs.edit_authors_dialog_ui import Ui_EditAuthorsDialog
-from calibre.gui2.dialogs.tag_list_editor import NotesUtilities, NotesTableWidgetItem
+from calibre.gui2.dialogs.tag_list_editor import NotesTableWidgetItem, NotesUtilities
 from calibre.utils.config import prefs
 from calibre.utils.config_base import tweaks
-from calibre.utils.icu import (
-    contains, lower as icu_lower, primary_contains, primary_startswith, sort_key,
-    upper as icu_upper,
-)
+from calibre.utils.icu import contains, primary_contains, primary_startswith, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 
 QT_HIDDEN_CLEAR_ACTION = '_q_qlineeditclearaction'
 
diff --git a/src/calibre/gui2/dialogs/edit_category_notes.py b/src/calibre/gui2/dialogs/edit_category_notes.py
index 36e082ff9c..23260a14dc 100644
--- a/src/calibre/gui2/dialogs/edit_category_notes.py
+++ b/src/calibre/gui2/dialogs/edit_category_notes.py
@@ -3,21 +3,38 @@
 
 import os
 import sys
-from qt.core import (
-    QButtonGroup, QByteArray, QDialog, QDialogButtonBox, QFormLayout, QHBoxLayout,
-    QIcon, QLabel, QLineEdit, QPixmap, QPushButton, QRadioButton, QSize, QSpinBox, Qt,
-    QTextDocument, QTextFrameFormat, QTextImageFormat, QUrl, QVBoxLayout, QWidget,
-    pyqtSlot,
-)
 from typing import NamedTuple
 
-from calibre import sanitize_file_name, fit_image
+from qt.core import (
+    QButtonGroup,
+    QByteArray,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QPixmap,
+    QPushButton,
+    QRadioButton,
+    QSize,
+    QSpinBox,
+    Qt,
+    QTextDocument,
+    QTextFrameFormat,
+    QTextImageFormat,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSlot,
+)
+
+from calibre import fit_image, sanitize_file_name
 from calibre.db.constants import RESOURCE_URL_SCHEME
 from calibre.db.notes.connect import hash_data
 from calibre.db.notes.exim import export_note, import_note
-from calibre.gui2 import (
-    Application, choose_files, choose_images, choose_save_file, error_dialog,
-)
+from calibre.gui2 import Application, choose_files, choose_images, choose_save_file, error_dialog
 from calibre.gui2.comments_editor import OBJECT_REPLACEMENT_CHAR, Editor, EditorWidget
 from calibre.gui2.widgets import ImageView
 from calibre.gui2.widgets2 import Dialog
diff --git a/src/calibre/gui2/dialogs/enum_values_edit.py b/src/calibre/gui2/dialogs/enum_values_edit.py
index 8a5884cf3d..3b87001cc6 100644
--- a/src/calibre/gui2/dialogs/enum_values_edit.py
+++ b/src/calibre/gui2/dialogs/enum_values_edit.py
@@ -1,9 +1,21 @@
 #!/usr/bin/env python
 # License: GPLv3 Copyright: 2020, Charles Haley
 
-from qt.core import (Qt, QDialog, QColor, QDialogButtonBox, QHeaderView,
-                     QGridLayout, QTableWidget, QTableWidgetItem, QVBoxLayout,
-                     QToolButton, QIcon, QAbstractItemView, QComboBox)
+from qt.core import (
+    QAbstractItemView,
+    QColor,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QHeaderView,
+    QIcon,
+    Qt,
+    QTableWidget,
+    QTableWidgetItem,
+    QToolButton,
+    QVBoxLayout,
+)
 
 from calibre.gui2 import error_dialog, gprefs
 
diff --git a/src/calibre/gui2/dialogs/exim.py b/src/calibre/gui2/dialogs/exim.py
index f0c9701ee3..dfceba8561 100644
--- a/src/calibre/gui2/dialogs/exim.py
+++ b/src/calibre/gui2/dialogs/exim.py
@@ -5,13 +5,30 @@
 import os
 import stat
 from functools import partial
-from qt.core import (
-    QAbstractItemView, QDialog, QDialogButtonBox, QFrame, QGridLayout, QIcon, QLabel,
-    QLineEdit, QListWidget, QListWidgetItem, QProgressBar, QPushButton, QScrollArea,
-    QSize, QStackedLayout, Qt, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Event, Thread
 
+from qt.core import (
+    QAbstractItemView,
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QGridLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QProgressBar,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QStackedLayout,
+    Qt,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import as_unicode, human_readable
 from calibre.constants import iswindows
 from calibre.db.legacy import LibraryDatabase
diff --git a/src/calibre/gui2/dialogs/match_books.py b/src/calibre/gui2/dialogs/match_books.py
index 790bf50a15..a64d9368d3 100644
--- a/src/calibre/gui2/dialogs/match_books.py
+++ b/src/calibre/gui2/dialogs/match_books.py
@@ -6,9 +6,7 @@ __copyright__ = '2013, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import (
-    QAbstractItemView, QApplication, QCursor, QDialog, Qt, QTableWidgetItem, QTimer,
-)
+from qt.core import QAbstractItemView, QApplication, QCursor, QDialog, Qt, QTableWidgetItem, QTimer
 
 from calibre.gui2 import error_dialog, gprefs
 from calibre.gui2.dialogs.match_books_ui import Ui_MatchBooks
diff --git a/src/calibre/gui2/dialogs/message_box.py b/src/calibre/gui2/dialogs/message_box.py
index 700355a5af..108061f591 100644
--- a/src/calibre/gui2/dialogs/message_box.py
+++ b/src/calibre/gui2/dialogs/message_box.py
@@ -5,12 +5,29 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from contextlib import suppress
 import sys
+from contextlib import suppress
+
 from qt.core import (
-    QAction, QApplication, QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon,
-    QKeySequence, QLabel, QPainter, QPlainTextEdit, QSize, QSizePolicy, Qt,
-    QTextBrowser, QTextDocument, QVBoxLayout, QWidget, pyqtSignal,
+    QAction,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QPainter,
+    QPlainTextEdit,
+    QSize,
+    QSizePolicy,
+    Qt,
+    QTextBrowser,
+    QTextDocument,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.constants import __version__, isfrozen
@@ -489,9 +506,10 @@ class JobError(QDialog):  # {{{
 
 
 if __name__ == '__main__':
+    from qt.core import QMainWindow, QTimer
+
     from calibre import prepare_string_for_xml
     from calibre.gui2 import Application, question_dialog
-    from qt.core import QMainWindow, QTimer
     app = Application([])
     merged = {'Kovid Goyal': ['Waterloo', 'Doomed'], 'Someone Else': ['Some other book ' * 1000]}
     lines = []
diff --git a/src/calibre/gui2/dialogs/metadata_bulk.py b/src/calibre/gui2/dialogs/metadata_bulk.py
index d8a2a564bd..85d4758294 100644
--- a/src/calibre/gui2/dialogs/metadata_bulk.py
+++ b/src/calibre/gui2/dialogs/metadata_bulk.py
@@ -3,38 +3,47 @@
 
 
 import numbers
-import regex
 from collections import defaultdict, namedtuple
 from io import BytesIO
-from qt.core import (
-    QComboBox, QCompleter, QDateTime, QDialog, QDialogButtonBox, QFont, QGridLayout,
-    QInputDialog, QLabel, QLineEdit, QProgressBar, QSize, Qt, QVBoxLayout, pyqtSignal,
-)
 from threading import Thread
 
+import regex
+from qt.core import (
+    QComboBox,
+    QCompleter,
+    QDateTime,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QGridLayout,
+    QInputDialog,
+    QLabel,
+    QLineEdit,
+    QProgressBar,
+    QSize,
+    Qt,
+    QVBoxLayout,
+    pyqtSignal,
+)
+
 from calibre import human_readable, prints
 from calibre.constants import DEBUG
 from calibre.db import _get_next_series_num_for_list
 from calibre.ebooks.metadata import authors_to_string, string_to_authors, title_sort
 from calibre.ebooks.metadata.book.formatter import SafeFormat
 from calibre.ebooks.metadata.opf2 import OPF
-from calibre.gui2 import (
-    UNDEFINED_QDATETIME, FunctionDispatcher, error_dialog, gprefs, info_dialog,
-    question_dialog,
-)
+from calibre.gui2 import UNDEFINED_QDATETIME, FunctionDispatcher, error_dialog, gprefs, info_dialog, question_dialog
 from calibre.gui2.custom_column_widgets import populate_metadata_page
 from calibre.gui2.dialogs.metadata_bulk_ui import Ui_MetadataBulkDialog
 from calibre.gui2.dialogs.tag_editor import TagEditor
 from calibre.gui2.dialogs.template_line_editor import TemplateLineEditor
-from calibre.gui2.widgets import (
-    LineEditECM, setup_status_actions, update_status_actions,
-)
+from calibre.gui2.widgets import LineEditECM, setup_status_actions, update_status_actions
 from calibre.startup import connect_lambda
 from calibre.utils.config import JSONConfig, dynamic, prefs, tweaks
 from calibre.utils.date import internal_iso_format_string, qt_to_dt
-from calibre.utils.icu import (
-    capitalize, lower as icu_lower, sort_key, upper as icu_upper,
-)
+from calibre.utils.icu import capitalize, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 from calibre.utils.localization import ngettext
 from calibre.utils.titlecase import titlecase
 from polyglot.builtins import error_message, iteritems, itervalues, native_string_type
@@ -321,9 +330,7 @@ class MyBlockingBusy(QDialog):  # {{{
 
         elif args.cover_action == 'trim':
             self.progress_next_step_range.emit(len(self.ids))
-            from calibre.utils.img import (
-                image_from_data, image_to_data, remove_borders_from_image,
-            )
+            from calibre.utils.img import image_from_data, image_to_data, remove_borders_from_image
             for book_id in self.ids:
                 cdata = cache.cover(book_id)
                 if cdata:
diff --git a/src/calibre/gui2/dialogs/multisort.py b/src/calibre/gui2/dialogs/multisort.py
index c9cbbb3cb7..07cb1dbe7e 100644
--- a/src/calibre/gui2/dialogs/multisort.py
+++ b/src/calibre/gui2/dialogs/multisort.py
@@ -2,10 +2,7 @@
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QAbstractItemView, QDialogButtonBox, QInputDialog, QLabel, QListWidget,
-    QListWidgetItem, QMenu, QSize, Qt, QVBoxLayout
-)
+from qt.core import QAbstractItemView, QDialogButtonBox, QInputDialog, QLabel, QListWidget, QListWidgetItem, QMenu, QSize, Qt, QVBoxLayout
 
 from calibre import prepare_string_for_xml
 from calibre.gui2 import error_dialog
diff --git a/src/calibre/gui2/dialogs/opml.py b/src/calibre/gui2/dialogs/opml.py
index ed56731d26..16455967a0 100644
--- a/src/calibre/gui2/dialogs/opml.py
+++ b/src/calibre/gui2/dialogs/opml.py
@@ -7,15 +7,12 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from collections import defaultdict, namedtuple
 from operator import itemgetter
 
-from qt.core import (
-    QDialog, QFormLayout, QHBoxLayout, QLineEdit, QToolButton, QIcon,
-    QDialogButtonBox, Qt, QSpinBox, QCheckBox)
-
 from lxml import etree
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QFormLayout, QHBoxLayout, QIcon, QLineEdit, QSpinBox, Qt, QToolButton
 
 from calibre.gui2 import choose_files, error_dialog
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.utils.icu import sort_key
+from calibre.utils.xml_parse import safe_xml_fromstring
 
 Group = namedtuple('Group', 'title feeds')
 
diff --git a/src/calibre/gui2/dialogs/palette.py b/src/calibre/gui2/dialogs/palette.py
index f22a57697b..2becff51b1 100644
--- a/src/calibre/gui2/dialogs/palette.py
+++ b/src/calibre/gui2/dialogs/palette.py
@@ -5,16 +5,27 @@
 import json
 import textwrap
 from contextlib import suppress
+
 from qt.core import (
-    QCheckBox, QComboBox, QDialog, QHBoxLayout, QIcon, QLabel, QPalette, QPushButton,
-    QScrollArea, QSize, QSizePolicy, QTabWidget, QVBoxLayout, QWidget, pyqtSignal,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QPalette,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QTabWidget,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.gui2 import Application, choose_files, choose_save_file, gprefs
-from calibre.gui2.palette import (
-    default_dark_palette, default_light_palette, is_foreground_color, palette_colors,
-    palette_from_dict,
-)
+from calibre.gui2.palette import default_dark_palette, default_light_palette, is_foreground_color, palette_colors, palette_from_dict
 from calibre.gui2.widgets2 import ColorButton, Dialog
 
 
diff --git a/src/calibre/gui2/dialogs/password.py b/src/calibre/gui2/dialogs/password.py
index 47a3f02c9d..fece539d80 100644
--- a/src/calibre/gui2/dialogs/password.py
+++ b/src/calibre/gui2/dialogs/password.py
@@ -2,10 +2,11 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
+
 from qt.core import QDialog, QLineEdit, Qt
 
-from calibre.gui2.dialogs.password_ui import Ui_Dialog
 from calibre.gui2 import dynamic
+from calibre.gui2.dialogs.password_ui import Ui_Dialog
 
 
 class PasswordDialog(QDialog, Ui_Dialog):
diff --git a/src/calibre/gui2/dialogs/plugin_updater.py b/src/calibre/gui2/dialogs/plugin_updater.py
index a05f49ed61..51787ea17f 100644
--- a/src/calibre/gui2/dialogs/plugin_updater.py
+++ b/src/calibre/gui2/dialogs/plugin_updater.py
@@ -8,21 +8,34 @@ __docformat__ = 'restructuredtext en'
 import datetime
 import re
 import traceback
+
 from qt.core import (
-    QAbstractItemView, QAbstractTableModel, QAction, QBrush, QComboBox, QDialog,
-    QDialogButtonBox, QFont, QFrame, QHBoxLayout, QIcon, QLabel, QLineEdit, QModelIndex,
-    QSize, QSortFilterProxyModel, Qt, QTableView, QUrl, QVBoxLayout,
+    QAbstractItemView,
+    QAbstractTableModel,
+    QAction,
+    QBrush,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFrame,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QModelIndex,
+    QSize,
+    QSortFilterProxyModel,
+    Qt,
+    QTableView,
+    QUrl,
+    QVBoxLayout,
 )
 
 from calibre import prints
-from calibre.constants import (
-    DEBUG, __appname__, __version__, ismacos, iswindows, numeric_version,
-)
+from calibre.constants import DEBUG, __appname__, __version__, ismacos, iswindows, numeric_version
 from calibre.customize import PluginInstallationType
-from calibre.customize.ui import (
-    NameConflict, add_plugin, disable_plugin, enable_plugin, has_external_plugins,
-    initialized_plugins, is_disabled, remove_plugin,
-)
+from calibre.customize.ui import NameConflict, add_plugin, disable_plugin, enable_plugin, has_external_plugins, initialized_plugins, is_disabled, remove_plugin
 from calibre.gui2 import error_dialog, gprefs, info_dialog, open_url, question_dialog
 from calibre.gui2.preferences.plugins import ConfigWidget
 from calibre.utils.date import UNDEFINED_DATE, format_date
diff --git a/src/calibre/gui2/dialogs/progress.py b/src/calibre/gui2/dialogs/progress.py
index 03c998b2ba..dc662931ee 100644
--- a/src/calibre/gui2/dialogs/progress.py
+++ b/src/calibre/gui2/dialogs/progress.py
@@ -5,9 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import (
-    QDialog, pyqtSignal, Qt, QVBoxLayout, QLabel, QFont, QProgressBar, QSize,
-    QDialogButtonBox, QApplication, QFontMetrics, QHBoxLayout, QIcon)
+from qt.core import QApplication, QDialog, QDialogButtonBox, QFont, QFontMetrics, QHBoxLayout, QIcon, QLabel, QProgressBar, QSize, Qt, QVBoxLayout, pyqtSignal
 
 from calibre.gui2 import elided_text, question_dialog
 from calibre.gui2.progress_indicator import ProgressIndicator
diff --git a/src/calibre/gui2/dialogs/quickview.py b/src/calibre/gui2/dialogs/quickview.py
index f1e0c633a2..ce6788c0a9 100644
--- a/src/calibre/gui2/dialogs/quickview.py
+++ b/src/calibre/gui2/dialogs/quickview.py
@@ -10,12 +10,25 @@ import traceback
 from functools import partial
 
 from qt.core import (
-    Qt, QDialog, QAbstractItemView, QTableWidgetItem, QIcon, QListWidgetItem,
-    QCoreApplication, QEvent, QObject, QApplication, pyqtSignal, QMenu,
-    QShortcut, QTimer, QStyle)
+    QAbstractItemView,
+    QApplication,
+    QCoreApplication,
+    QDialog,
+    QEvent,
+    QIcon,
+    QListWidgetItem,
+    QMenu,
+    QObject,
+    QShortcut,
+    QStyle,
+    Qt,
+    QTableWidgetItem,
+    QTimer,
+    pyqtSignal,
+)
 
 from calibre.customize.ui import find_plugin
-from calibre.gui2 import gprefs, error_dialog
+from calibre.gui2 import error_dialog, gprefs
 from calibre.gui2.dialogs.quickview_ui import Ui_Quickview
 from calibre.utils.date import timestampfromdt
 from calibre.utils.icu import sort_key
diff --git a/src/calibre/gui2/dialogs/restore_library.py b/src/calibre/gui2/dialogs/restore_library.py
index 46c75b4601..4997e9e1d8 100644
--- a/src/calibre/gui2/dialogs/restore_library.py
+++ b/src/calibre/gui2/dialogs/restore_library.py
@@ -2,13 +2,11 @@
 # License: GPLv3 Copyright: 2011, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (QDialog, QLabel, QVBoxLayout, QDialogButtonBox,
-        QProgressBar, QSize, QTimer, pyqtSignal, Qt)
+from qt.core import QDialog, QDialogButtonBox, QLabel, QProgressBar, QSize, Qt, QTimer, QVBoxLayout, pyqtSignal
 
-from calibre.gui2 import (error_dialog, question_dialog, warning_dialog,
-    info_dialog)
 from calibre import force_unicode
 from calibre.constants import filesystem_encoding
+from calibre.gui2 import error_dialog, info_dialog, question_dialog, warning_dialog
 
 
 class DBRestore(QDialog):
diff --git a/src/calibre/gui2/dialogs/saved_search_editor.py b/src/calibre/gui2/dialogs/saved_search_editor.py
index 1a8b83274c..f5fde04f51 100644
--- a/src/calibre/gui2/dialogs/saved_search_editor.py
+++ b/src/calibre/gui2/dialogs/saved_search_editor.py
@@ -2,16 +2,14 @@
 # License: GPLv3 Copyright: 2008, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QDialog, QDialogButtonBox, QFormLayout, QIcon, QLabel, QLineEdit, QListWidget,
-    QPlainTextEdit, Qt, QVBoxLayout,
-)
+from qt.core import QDialog, QDialogButtonBox, QFormLayout, QIcon, QLabel, QLineEdit, QListWidget, QPlainTextEdit, Qt, QVBoxLayout
 
 from calibre import prepare_string_for_xml
 from calibre.gui2 import error_dialog
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.widgets2 import Dialog
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 
 
 def commit_searches(searches):
diff --git a/src/calibre/gui2/dialogs/scheduler.py b/src/calibre/gui2/dialogs/scheduler.py
index 9009e7db9d..517e25ef4b 100644
--- a/src/calibre/gui2/dialogs/scheduler.py
+++ b/src/calibre/gui2/dialogs/scheduler.py
@@ -6,26 +6,55 @@ __docformat__ = 'restructuredtext en'
 Scheduler for automated recipe downloads
 '''
 
-from datetime import timedelta
-import calendar, textwrap
+import calendar
+import textwrap
 from collections import OrderedDict
 from contextlib import suppress
+from datetime import timedelta
 
 from qt.core import (
-    QDialog, Qt, QTime, QObject, QMenu, QHBoxLayout, QAction, QIcon, QRecursiveMutex,
-    QTimer, pyqtSignal, QWidget, QGridLayout, QCheckBox, QTimeEdit, QLabel,
-    QLineEdit, QDoubleSpinBox, QSize, QTreeView, QSizePolicy, QToolButton,
-    QFrame, QVBoxLayout, QTabWidget, QSpacerItem, QGroupBox,
-    QRadioButton, QStackedWidget, QSpinBox, QPushButton, QDialogButtonBox
+    QAction,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QDoubleSpinBox,
+    QFrame,
+    QGridLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QMenu,
+    QObject,
+    QPushButton,
+    QRadioButton,
+    QRecursiveMutex,
+    QSize,
+    QSizePolicy,
+    QSpacerItem,
+    QSpinBox,
+    QStackedWidget,
+    Qt,
+    QTabWidget,
+    QTime,
+    QTimeEdit,
+    QTimer,
+    QToolButton,
+    QTreeView,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
-from calibre.gui2 import config as gconf, error_dialog, gprefs
-from calibre.gui2.search_box import SearchBox2
-from calibre.web.feeds.recipes.model import RecipeModel
-from calibre.utils.date import utcnow
-from calibre.utils.network import internet_connected
 from calibre import force_unicode
-from calibre.utils.localization import get_lang, canonicalize_lang
+from calibre.gui2 import config as gconf
+from calibre.gui2 import error_dialog, gprefs
+from calibre.gui2.search_box import SearchBox2
+from calibre.utils.date import utcnow
+from calibre.utils.localization import canonicalize_lang, get_lang
+from calibre.utils.network import internet_connected
+from calibre.web.feeds.recipes.model import RecipeModel
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/gui2/dialogs/search.py b/src/calibre/gui2/dialogs/search.py
index f5794fc335..106806538d 100644
--- a/src/calibre/gui2/dialogs/search.py
+++ b/src/calibre/gui2/dialogs/search.py
@@ -4,10 +4,27 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import copy
 import re
 from datetime import date
+
 from qt.core import (
-    QComboBox, QDialog, QDialogButtonBox, QFormLayout, QFrame, QGroupBox, QHBoxLayout,
-    QIcon, QLabel, QLineEdit, QPushButton, QRadioButton, QSize, QSpinBox, Qt,
-    QTabWidget, QToolButton, QVBoxLayout, QWidget,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QFrame,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QPushButton,
+    QRadioButton,
+    QSize,
+    QSpinBox,
+    Qt,
+    QTabWidget,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
 )
 
 from calibre import strftime
diff --git a/src/calibre/gui2/dialogs/select_formats.py b/src/calibre/gui2/dialogs/select_formats.py
index a17ae49995..49ec4fd96b 100644
--- a/src/calibre/gui2/dialogs/select_formats.py
+++ b/src/calibre/gui2/dialogs/select_formats.py
@@ -6,8 +6,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import QVBoxLayout, QDialog, QLabel, QDialogButtonBox, Qt, \
-        QAbstractListModel, QListView, QSize, QApplication, QAbstractItemView
+from qt.core import QAbstractItemView, QAbstractListModel, QApplication, QDialog, QDialogButtonBox, QLabel, QListView, QSize, Qt, QVBoxLayout
 
 from calibre.gui2 import file_icon_provider
 
diff --git a/src/calibre/gui2/dialogs/show_category_note.py b/src/calibre/gui2/dialogs/show_category_note.py
index 737312deb6..428357620c 100644
--- a/src/calibre/gui2/dialogs/show_category_note.py
+++ b/src/calibre/gui2/dialogs/show_category_note.py
@@ -2,10 +2,8 @@
 # License: GPLv3 Copyright: 2023, Kovid Goyal <kovid at kovidgoyal.net>
 
 import os
-from qt.core import (
-    QApplication, QByteArray, QDialog, QDialogButtonBox, QIcon, QLabel, QMimeData,
-    QSize, Qt, QTextDocument, QUrl, QVBoxLayout,
-)
+
+from qt.core import QApplication, QByteArray, QDialog, QDialogButtonBox, QIcon, QLabel, QMimeData, QSize, Qt, QTextDocument, QUrl, QVBoxLayout
 
 from calibre import prepare_string_for_xml
 from calibre.db.constants import RESOURCE_URL_SCHEME
diff --git a/src/calibre/gui2/dialogs/smartdevice.py b/src/calibre/gui2/dialogs/smartdevice.py
index 2b0bd7d7bc..a47cd42745 100644
--- a/src/calibre/gui2/dialogs/smartdevice.py
+++ b/src/calibre/gui2/dialogs/smartdevice.py
@@ -3,7 +3,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from qt.core import (QDialog, QLineEdit, Qt)
+from qt.core import QDialog, QLineEdit, Qt
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.dialogs.smartdevice_ui import Ui_Dialog
diff --git a/src/calibre/gui2/dialogs/tag_categories.py b/src/calibre/gui2/dialogs/tag_categories.py
index 915f946926..ab591ba5c8 100644
--- a/src/calibre/gui2/dialogs/tag_categories.py
+++ b/src/calibre/gui2/dialogs/tag_categories.py
@@ -1,16 +1,16 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from collections import namedtuple, defaultdict
+from collections import defaultdict, namedtuple
+
 from qt.core import QApplication, QDialog, QIcon, QListWidgetItem, Qt
 
 from calibre.constants import islinux
 from calibre.gui2 import error_dialog, warning_dialog
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.dialogs.tag_categories_ui import Ui_TagCategories
-from calibre.utils.icu import (
-    lower as icu_lower, primary_contains, primary_sort_key, strcmp,
-)
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import primary_contains, primary_sort_key, strcmp
 
 
 class TagCategories(QDialog, Ui_TagCategories):
diff --git a/src/calibre/gui2/dialogs/tag_editor.py b/src/calibre/gui2/dialogs/tag_editor.py
index 1a979546ed..fdf90af097 100644
--- a/src/calibre/gui2/dialogs/tag_editor.py
+++ b/src/calibre/gui2/dialogs/tag_editor.py
@@ -1,9 +1,7 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from qt.core import (
-    QAbstractItemView, QDialog, QSortFilterProxyModel, QStringListModel, Qt,
-)
+from qt.core import QAbstractItemView, QDialog, QSortFilterProxyModel, QStringListModel, Qt
 
 from calibre.constants import islinux
 from calibre.gui2 import error_dialog, gprefs, question_dialog
diff --git a/src/calibre/gui2/dialogs/tag_list_editor.py b/src/calibre/gui2/dialogs/tag_list_editor.py
index afb6390b1e..b8c7f9ee13 100644
--- a/src/calibre/gui2/dialogs/tag_list_editor.py
+++ b/src/calibre/gui2/dialogs/tag_list_editor.py
@@ -7,14 +7,27 @@ from contextlib import contextmanager
 from functools import partial
 
 from qt.core import (
-    QAbstractItemView, QAction, QApplication, QColor, QDialog,
-    QDialogButtonBox, QFrame, QIcon, QLabel, QMenu, QSize, QStyledItemDelegate,
-    Qt, QTableWidgetItem, QTimer, pyqtSignal, sip,
+    QAbstractItemView,
+    QAction,
+    QApplication,
+    QColor,
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QIcon,
+    QLabel,
+    QMenu,
+    QSize,
+    QStyledItemDelegate,
+    Qt,
+    QTableWidgetItem,
+    QTimer,
+    pyqtSignal,
+    sip,
 )
 
 from calibre import sanitize_file_name
-from calibre.gui2 import (error_dialog, gprefs, question_dialog, choose_files,
-                          choose_save_file)
+from calibre.gui2 import choose_files, choose_save_file, error_dialog, gprefs, question_dialog
 from calibre.gui2.actions.show_quickview import get_quickview_action_plugin
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.gui2.dialogs.confirm_delete import confirm
@@ -22,10 +35,9 @@ from calibre.gui2.dialogs.tag_list_editor_table_widget import TleTableWidget
 from calibre.gui2.dialogs.tag_list_editor_ui import Ui_TagListEditor
 from calibre.gui2.widgets import EnLineEdit
 from calibre.utils.config import prefs
-from calibre.utils.icu import (
-    capitalize, contains, lower as icu_lower, primary_contains, primary_startswith,
-    upper as icu_upper,
-)
+from calibre.utils.icu import capitalize, contains, primary_contains, primary_startswith
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 from calibre.utils.titlecase import titlecase
 
 QT_HIDDEN_CLEAR_ACTION = '_q_qlineeditclearaction'
diff --git a/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py b/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py
index 1075c222dc..a6bafda8f8 100644
--- a/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py
+++ b/src/calibre/gui2/dialogs/tag_list_editor_table_widget.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 # License: GPLv3 Copyright: 2008, Kovid Goyal <kovid at kovidgoyal.net>
 
-from qt.core import (Qt, QTableWidget, pyqtSignal)
+from qt.core import Qt, QTableWidget, pyqtSignal
 
 
 class TleTableWidget(QTableWidget):
diff --git a/src/calibre/gui2/dialogs/template_dialog.py b/src/calibre/gui2/dialogs/template_dialog.py
index add80773e2..f6aba1f406 100644
--- a/src/calibre/gui2/dialogs/template_dialog.py
+++ b/src/calibre/gui2/dialogs/template_dialog.py
@@ -11,28 +11,46 @@ import re
 import sys
 import traceback
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QApplication, QColor, QComboBox, QCursor, QDialog,
-    QDialogButtonBox, QFont, QFontDatabase, QFontInfo, QFontMetrics, QIcon, QLineEdit,
-    QPalette, QSize, QSyntaxHighlighter, Qt, QTableWidget, QTableWidgetItem,
-    QTextCharFormat, QTextOption, QVBoxLayout, pyqtSignal,
+    QAbstractItemView,
+    QApplication,
+    QColor,
+    QComboBox,
+    QCursor,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFontDatabase,
+    QFontInfo,
+    QFontMetrics,
+    QIcon,
+    QLineEdit,
+    QPalette,
+    QSize,
+    QSyntaxHighlighter,
+    Qt,
+    QTableWidget,
+    QTableWidgetItem,
+    QTextCharFormat,
+    QTextOption,
+    QVBoxLayout,
+    pyqtSignal,
 )
 
 from calibre import sanitize_file_name
 from calibre.constants import config_dir
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.book.formatter import SafeFormat
-from calibre.gui2 import (
-    choose_files, choose_save_file, error_dialog, gprefs, pixmap_to_data,
-    question_dialog,
-)
+from calibre.gui2 import choose_files, choose_save_file, error_dialog, gprefs, pixmap_to_data, question_dialog
 from calibre.gui2.dialogs.template_dialog_ui import Ui_TemplateDialog
 from calibre.library.coloring import color_row_key, displayable_columns
 from calibre.utils.config_base import tweaks
 from calibre.utils.date import DEFAULT_DATE
 from calibre.utils.formatter import PythonTemplateContext, StopException
 from calibre.utils.formatter_functions import StoredObjectType, formatter_functions
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 from calibre.utils.localization import localize_user_manual_link, ngettext
 from calibre.utils.resources import get_path as P
 
diff --git a/src/calibre/gui2/dialogs/template_dialog_box_layout.py b/src/calibre/gui2/dialogs/template_dialog_box_layout.py
index 91061ead42..ea8e13048f 100644
--- a/src/calibre/gui2/dialogs/template_dialog_box_layout.py
+++ b/src/calibre/gui2/dialogs/template_dialog_box_layout.py
@@ -4,7 +4,7 @@ Created on 20 Jan 2021
 @author: Charles Haley
 '''
 
-from qt.core import (QBoxLayout)
+from qt.core import QBoxLayout
 
 
 class BoxLayout(QBoxLayout):
diff --git a/src/calibre/gui2/dialogs/template_dialog_code_widget.py b/src/calibre/gui2/dialogs/template_dialog_code_widget.py
index a0eedd4981..196eaab1ee 100644
--- a/src/calibre/gui2/dialogs/template_dialog_code_widget.py
+++ b/src/calibre/gui2/dialogs/template_dialog_code_widget.py
@@ -7,10 +7,7 @@ Based on classes in calibre.gui2.tweak_book.editor
 License: GPLv3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 '''
 
-from qt.core import (
-    QFont, QPainter, QPalette, QPlainTextEdit, QRect, Qt, QTextEdit,
-    QTextFormat, QTextCursor
-)
+from qt.core import QFont, QPainter, QPalette, QPlainTextEdit, QRect, Qt, QTextCursor, QTextEdit, QTextFormat
 
 from calibre.gui2.tweak_book.editor.text import LineNumbers
 from calibre.gui2.tweak_book.editor.themes import get_theme, theme_color
diff --git a/src/calibre/gui2/dialogs/trim_image.py b/src/calibre/gui2/dialogs/trim_image.py
index c6842fc3db..0837b6629c 100644
--- a/src/calibre/gui2/dialogs/trim_image.py
+++ b/src/calibre/gui2/dialogs/trim_image.py
@@ -6,10 +6,8 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 import sys
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QFormLayout, QHBoxLayout, QIcon, QKeySequence,
-    QLabel, QSize, QSpinBox, Qt, QToolBar, QVBoxLayout,
-)
+
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QFormLayout, QHBoxLayout, QIcon, QKeySequence, QLabel, QSize, QSpinBox, Qt, QToolBar, QVBoxLayout
 
 from calibre.gui2 import gprefs
 from calibre.gui2.tweak_book.editor.canvas import Canvas
diff --git a/src/calibre/gui2/dnd.py b/src/calibre/gui2/dnd.py
index 1a2b5bba08..532321e0f1 100644
--- a/src/calibre/gui2/dnd.py
+++ b/src/calibre/gui2/dnd.py
@@ -8,12 +8,10 @@ __docformat__ = 'restructuredtext en'
 import os
 import posixpath
 import re
-from qt.core import (
-    QDialog, QDialogButtonBox, QImageReader, QLabel, QPixmap, QProgressBar, Qt,
-    QTimer, QUrl, QVBoxLayout
-)
-from threading import Thread
 from contextlib import suppress
+from threading import Thread
+
+from qt.core import QDialog, QDialogButtonBox, QImageReader, QLabel, QPixmap, QProgressBar, Qt, QTimer, QUrl, QVBoxLayout
 
 from calibre import as_unicode, browser, prints
 from calibre.constants import DEBUG, iswindows
diff --git a/src/calibre/gui2/ebook_download.py b/src/calibre/gui2/ebook_download.py
index 1306c1a2bf..389bf7b02c 100644
--- a/src/calibre/gui2/ebook_download.py
+++ b/src/calibre/gui2/ebook_download.py
@@ -6,6 +6,7 @@ import os
 import shutil
 import time
 from contextlib import closing
+
 from mechanize import MozillaCookieJar
 
 from calibre import browser
diff --git a/src/calibre/gui2/email.py b/src/calibre/gui2/email.py
index 77e36bcb74..894c69087b 100644
--- a/src/calibre/gui2/email.py
+++ b/src/calibre/gui2/email.py
@@ -12,12 +12,10 @@ import time
 from collections import defaultdict
 from functools import partial
 from itertools import repeat
-from qt.core import (
-    QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QLineEdit, QListWidget,
-    QListWidgetItem, QPushButton, Qt,
-)
 from threading import Thread
 
+from qt.core import QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QLineEdit, QListWidget, QListWidgetItem, QPushButton, Qt
+
 from calibre.constants import preferred_encoding
 from calibre.customize.ui import available_input_formats, available_output_formats
 from calibre.ebooks.metadata import authors_to_string
@@ -27,9 +25,8 @@ from calibre.library.save_to_disk import get_components
 from calibre.utils.config import prefs, tweaks
 from calibre.utils.icu import primary_sort_key
 from calibre.utils.resources import get_image_path as I
-from calibre.utils.smtp import (
-    compose_mail, config as email_config, extract_email_address, sendmail,
-)
+from calibre.utils.smtp import compose_mail, extract_email_address, sendmail
+from calibre.utils.smtp import config as email_config
 from polyglot.binary import from_hex_unicode
 from polyglot.builtins import iteritems, itervalues
 
diff --git a/src/calibre/gui2/extra_files_watcher.py b/src/calibre/gui2/extra_files_watcher.py
index 41b34a2462..0a933679cf 100644
--- a/src/calibre/gui2/extra_files_watcher.py
+++ b/src/calibre/gui2/extra_files_watcher.py
@@ -2,10 +2,11 @@
 # License: GPLv3 Copyright: 2023, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import QObject, QTimer
 from time import monotonic
 from typing import NamedTuple, Tuple
 
+from qt.core import QObject, QTimer
+
 from calibre.db.constants import DATA_FILE_PATTERN
 
 
diff --git a/src/calibre/gui2/flow_toolbar.py b/src/calibre/gui2/flow_toolbar.py
index 01ec3e1b97..013aa55515 100644
--- a/src/calibre/gui2/flow_toolbar.py
+++ b/src/calibre/gui2/flow_toolbar.py
@@ -2,10 +2,7 @@
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QPoint, QRect, QSize, QSizePolicy, QStyle, QStyleOption, QStylePainter, Qt,
-    QToolBar, QToolButton, QWidget, pyqtSignal
-)
+from qt.core import QPoint, QRect, QSize, QSizePolicy, QStyle, QStyleOption, QStylePainter, Qt, QToolBar, QToolButton, QWidget, pyqtSignal
 
 
 class Separator(QWidget):
diff --git a/src/calibre/gui2/font_family_chooser.py b/src/calibre/gui2/font_family_chooser.py
index 0d2ee0ece1..387785a6eb 100644
--- a/src/calibre/gui2/font_family_chooser.py
+++ b/src/calibre/gui2/font_family_chooser.py
@@ -7,11 +7,35 @@ __docformat__ = 'restructuredtext en'
 
 import os
 import shutil
+
 from qt.core import (
-    QAbstractItemView, QDialog, QDialogButtonBox, QFont, QFontComboBox, QFontDatabase,
-    QFontInfo, QFontMetrics, QGridLayout, QHBoxLayout, QIcon, QLabel, QLineEdit,
-    QListView, QPen, QPushButton, QRawFont, QSize, QSizePolicy, QStringListModel,
-    QStyle, QStyledItemDelegate, Qt, QToolButton, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFontComboBox,
+    QFontDatabase,
+    QFontInfo,
+    QFontMetrics,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QPen,
+    QPushButton,
+    QRawFont,
+    QSize,
+    QSizePolicy,
+    QStringListModel,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.constants import config_dir
diff --git a/src/calibre/gui2/fts/dialog.py b/src/calibre/gui2/fts/dialog.py
index 0b62e63592..357a04c855 100644
--- a/src/calibre/gui2/fts/dialog.py
+++ b/src/calibre/gui2/fts/dialog.py
@@ -3,10 +3,8 @@
 
 
 import os
-from qt.core import (
-    QAction, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QSize, QStackedWidget, Qt,
-    QVBoxLayout,
-)
+
+from qt.core import QAction, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QSize, QStackedWidget, Qt, QVBoxLayout
 
 from calibre.gui2 import error_dialog, warning_dialog
 from calibre.gui2.fts.scan import ScanStatus
diff --git a/src/calibre/gui2/fts/scan.py b/src/calibre/gui2/fts/scan.py
index dea28d6f74..99a69911b5 100644
--- a/src/calibre/gui2/fts/scan.py
+++ b/src/calibre/gui2/fts/scan.py
@@ -2,10 +2,8 @@
 # License: GPL v3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
 
 import os
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QPushButton,
-    QRadioButton, QVBoxLayout, QWidget, pyqtSignal
-)
+
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QPushButton, QRadioButton, QVBoxLayout, QWidget, pyqtSignal
 
 from calibre.db.listeners import EventType
 from calibre.db.utils import IndexingProgress
diff --git a/src/calibre/gui2/fts/search.py b/src/calibre/gui2/fts/search.py
index 2c134715f5..d2689c031b 100644
--- a/src/calibre/gui2/fts/search.py
+++ b/src/calibre/gui2/fts/search.py
@@ -9,20 +9,39 @@ import traceback
 from contextlib import suppress
 from functools import partial
 from itertools import count
-from qt.core import (
-    QAbstractItemModel, QAbstractItemView, QAction, QCheckBox, QDialog,
-    QDialogButtonBox, QFont, QHBoxLayout, QIcon, QKeySequence, QLabel, QMenu,
-    QModelIndex, QPixmap, QPushButton, QRect, QSize, QSplitter, QStackedWidget, Qt,
-    QTreeView, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Event, Thread
 
+from qt.core import (
+    QAbstractItemModel,
+    QAbstractItemView,
+    QAction,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QMenu,
+    QModelIndex,
+    QPixmap,
+    QPushButton,
+    QRect,
+    QSize,
+    QSplitter,
+    QStackedWidget,
+    Qt,
+    QTreeView,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import fit_image, prepare_string_for_xml
 from calibre.db import FTSQueryError
 from calibre.ebooks.metadata import authors_to_string, fmt_sidx
-from calibre.gui2 import (
-    config, error_dialog, gprefs, info_dialog, question_dialog, safe_open_url,
-)
+from calibre.gui2 import config, error_dialog, gprefs, info_dialog, question_dialog, safe_open_url
 from calibre.gui2.fts.utils import get_db
 from calibre.gui2.library.models import render_pin
 from calibre.gui2.progress_indicator import ProgressIndicator
diff --git a/src/calibre/gui2/geometry.py b/src/calibre/gui2/geometry.py
index 91a3e5ab6d..12795e942d 100644
--- a/src/calibre/gui2/geometry.py
+++ b/src/calibre/gui2/geometry.py
@@ -6,7 +6,8 @@
 # our own restore geometry
 
 
-from qt.core import QRect, QScreen, QSize, QWidget, QApplication, Qt
+from qt.core import QApplication, QRect, QScreen, QSize, Qt, QWidget
+
 from calibre.constants import is_debugging as _is_debugging
 from calibre.utils.config_base import tweaks
 
diff --git a/src/calibre/gui2/gestures.py b/src/calibre/gui2/gestures.py
index 1b60d1951c..19198f2dc6 100644
--- a/src/calibre/gui2/gestures.py
+++ b/src/calibre/gui2/gestures.py
@@ -4,10 +4,8 @@
 
 import os
 from functools import lru_cache
-from qt.core import (
-    QApplication, QEvent, QInputDevice, QMouseEvent, QObject, QPointF, QScroller, Qt,
-    pyqtSignal,
-)
+
+from qt.core import QApplication, QEvent, QInputDevice, QMouseEvent, QObject, QPointF, QScroller, Qt, pyqtSignal
 
 from calibre.startup import connect_lambda
 from calibre.utils.monotonic import monotonic
diff --git a/src/calibre/gui2/html_transform_rules.py b/src/calibre/gui2/html_transform_rules.py
index 035b1a6293..bf632d0525 100644
--- a/src/calibre/gui2/html_transform_rules.py
+++ b/src/calibre/gui2/html_transform_rules.py
@@ -2,25 +2,18 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QComboBox, QFrame, QHBoxLayout, QIcon, QLabel, QLineEdit, QPushButton,
-    QScrollArea, Qt, QToolButton, QVBoxLayout, QWidget, pyqtSignal
-)
+from qt.core import QComboBox, QFrame, QHBoxLayout, QIcon, QLabel, QLineEdit, QPushButton, QScrollArea, Qt, QToolButton, QVBoxLayout, QWidget, pyqtSignal
 
 from calibre import prepare_string_for_xml
-from calibre.ebooks.html_transform_rules import (
-    ACTION_MAP, MATCH_TYPE_MAP, export_rules, import_rules, transform_html,
-    validate_rule
-)
+from calibre.ebooks.html_transform_rules import ACTION_MAP, MATCH_TYPE_MAP, export_rules, import_rules, transform_html, validate_rule
 from calibre.gui2 import elided_text, error_dialog
 from calibre.gui2.convert.xpath_wizard import XPathEdit
-from calibre.gui2.css_transform_rules import (
-    RulesWidget as RulesWidgetBase, Tester as TesterBase
-)
-from calibre.gui2.tag_mapper import (
-    RuleEditDialog as RuleEditDialogBase, RuleItem as RuleItemBase,
-    Rules as RulesBase, RulesDialog as RulesDialogBase
-)
+from calibre.gui2.css_transform_rules import RulesWidget as RulesWidgetBase
+from calibre.gui2.css_transform_rules import Tester as TesterBase
+from calibre.gui2.tag_mapper import RuleEditDialog as RuleEditDialogBase
+from calibre.gui2.tag_mapper import RuleItem as RuleItemBase
+from calibre.gui2.tag_mapper import Rules as RulesBase
+from calibre.gui2.tag_mapper import RulesDialog as RulesDialogBase
 
 # Classes for rule edit widget {{{
 
diff --git a/src/calibre/gui2/icon_theme.py b/src/calibre/gui2/icon_theme.py
index e33b583354..aa94005d13 100644
--- a/src/calibre/gui2/icon_theme.py
+++ b/src/calibre/gui2/icon_theme.py
@@ -17,23 +17,50 @@ from functools import lru_cache
 from io import BytesIO
 from itertools import count
 from multiprocessing.pool import ThreadPool
-from qt.core import (
-    QAbstractItemView, QApplication, QCheckBox, QComboBox, QDialog, QDialogButtonBox,
-    QFormLayout, QGroupBox, QHBoxLayout, QIcon, QImage, QImageReader,
-    QItemSelectionModel, QLabel, QLineEdit, QListWidget, QListWidgetItem, QPen, QPixmap,
-    QProgressDialog, QSize, QSpinBox, QSplitter, QStackedLayout, QStaticText, QStyle,
-    QStyledItemDelegate, Qt, QTabWidget, QTextEdit, QVBoxLayout, QWidget, pyqtSignal,
-    sip,
-)
 from threading import Event, Thread
 
-from calibre import detect_ncpus as cpu_count, fit_image, human_readable, walk
+from qt.core import (
+    QAbstractItemView,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QImage,
+    QImageReader,
+    QItemSelectionModel,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QPen,
+    QPixmap,
+    QProgressDialog,
+    QSize,
+    QSpinBox,
+    QSplitter,
+    QStackedLayout,
+    QStaticText,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTabWidget,
+    QTextEdit,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+    sip,
+)
+
+from calibre import detect_ncpus as cpu_count
+from calibre import fit_image, human_readable, walk
 from calibre.constants import cache_dir
 from calibre.customize.ui import interface_actions
-from calibre.gui2 import (
-    choose_dir, choose_save_file, empty_index, error_dialog, gprefs,
-    icon_resource_manager, must_use_qt, safe_open_url,
-)
+from calibre.gui2 import choose_dir, choose_save_file, empty_index, error_dialog, gprefs, icon_resource_manager, must_use_qt, safe_open_url
 from calibre.gui2.dialogs.progress import ProgressDialog
 from calibre.gui2.progress_indicator import ProgressIndicator
 from calibre.gui2.widgets2 import Dialog
@@ -42,7 +69,8 @@ from calibre.utils.filenames import ascii_filename, atomic_rename
 from calibre.utils.https import HTTPError, get_https_resource_securely
 from calibre.utils.icu import numeric_sort_key as sort_key
 from calibre.utils.img import Canvas, image_from_data, optimize_jpeg, optimize_png
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from calibre.utils.zipfile import ZIP_STORED, ZipFile
 from polyglot import http_client
 from polyglot.builtins import as_bytes, iteritems, reraise
diff --git a/src/calibre/gui2/image_popup.py b/src/calibre/gui2/image_popup.py
index 2af9eb4d88..161dfa0890 100644
--- a/src/calibre/gui2/image_popup.py
+++ b/src/calibre/gui2/image_popup.py
@@ -6,15 +6,31 @@ __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from qt.core import (
-    QApplication, QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon, QImage,
-    QLabel, QPainter, QPalette, QPixmap, QScrollArea, QSize, QSizePolicy,
-    Qt, QTransform, QUrl, QVBoxLayout, pyqtSignal, QAction, QKeySequence
+    QAction,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QHBoxLayout,
+    QIcon,
+    QImage,
+    QKeySequence,
+    QLabel,
+    QPainter,
+    QPalette,
+    QPixmap,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    Qt,
+    QTransform,
+    QUrl,
+    QVBoxLayout,
+    pyqtSignal,
 )
 
 from calibre import fit_image
-from calibre.gui2 import (
-    NO_URL_FORMATTING, choose_save_file, gprefs, max_available_height
-)
+from calibre.gui2 import NO_URL_FORMATTING, choose_save_file, gprefs, max_available_height
 
 
 def render_svg(widget, path):
diff --git a/src/calibre/gui2/init.py b/src/calibre/gui2/init.py
index b7d2a09c34..ee3b4e7758 100644
--- a/src/calibre/gui2/init.py
+++ b/src/calibre/gui2/init.py
@@ -6,10 +6,26 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import functools
+
 from qt.core import (
-    QAction, QApplication, QDialog, QEvent, QIcon, QLabel, QMenu, QPixmap,
-    QStackedWidget, QStatusBar, QStyle, QStyleOption, QStylePainter, Qt, QTabBar,
-    QTimer, QToolButton, QUrl,
+    QAction,
+    QApplication,
+    QDialog,
+    QEvent,
+    QIcon,
+    QLabel,
+    QMenu,
+    QPixmap,
+    QStackedWidget,
+    QStatusBar,
+    QStyle,
+    QStyleOption,
+    QStylePainter,
+    Qt,
+    QTabBar,
+    QTimer,
+    QToolButton,
+    QUrl,
 )
 
 from calibre.constants import get_appname_for_display, get_version, ismacos
diff --git a/src/calibre/gui2/job_indicator.py b/src/calibre/gui2/job_indicator.py
index a87e55b38a..504867a409 100644
--- a/src/calibre/gui2/job_indicator.py
+++ b/src/calibre/gui2/job_indicator.py
@@ -5,10 +5,7 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import (
-    QAbstractAnimation, QBrush, QColor, QEasingCurve, QPainter, QPainterPath,
-    QPalette, QPoint, QPointF, QPropertyAnimation, QRect, Qt, QWidget
-)
+from qt.core import QAbstractAnimation, QBrush, QColor, QEasingCurve, QPainter, QPainterPath, QPalette, QPoint, QPointF, QPropertyAnimation, QRect, Qt, QWidget
 
 from calibre.gui2 import config
 
diff --git a/src/calibre/gui2/jobs.py b/src/calibre/gui2/jobs.py
index 6b1368e94e..4ee717eb05 100644
--- a/src/calibre/gui2/jobs.py
+++ b/src/calibre/gui2/jobs.py
@@ -10,12 +10,37 @@ Job management.
 '''
 
 import time
+
 from qt.core import (
-    QAbstractItemDelegate, QAbstractTableModel, QAction, QApplication, QByteArray,
-    QCoreApplication, QDialog, QDialogButtonBox, QEvent, QHBoxLayout, QIcon,
-    QItemSelectionModel, QLabel, QModelIndex, QPlainTextEdit, QSize, QSizePolicy,
-    QSortFilterProxyModel, QStyle, QStyleOption, QStyleOptionProgressBar, QStylePainter,
-    Qt, QTextBrowser, QTimer, QToolTip, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractItemDelegate,
+    QAbstractTableModel,
+    QAction,
+    QApplication,
+    QByteArray,
+    QCoreApplication,
+    QDialog,
+    QDialogButtonBox,
+    QEvent,
+    QHBoxLayout,
+    QIcon,
+    QItemSelectionModel,
+    QLabel,
+    QModelIndex,
+    QPlainTextEdit,
+    QSize,
+    QSizePolicy,
+    QSortFilterProxyModel,
+    QStyle,
+    QStyleOption,
+    QStyleOptionProgressBar,
+    QStylePainter,
+    Qt,
+    QTextBrowser,
+    QTimer,
+    QToolTip,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import __appname__, as_unicode, strftime
diff --git a/src/calibre/gui2/keyboard.py b/src/calibre/gui2/keyboard.py
index 0eb9ce1056..83f32662ca 100644
--- a/src/calibre/gui2/keyboard.py
+++ b/src/calibre/gui2/keyboard.py
@@ -8,19 +8,47 @@ __docformat__ = 'restructuredtext en'
 from collections import OrderedDict
 from functools import partial
 
-from qt.core import (QObject, QKeySequence, QAbstractItemModel, QModelIndex, QItemSelectionModel,
-        Qt, QStyledItemDelegate, QTextDocument, QStyle, pyqtSignal, QFrame, QAbstractItemView, QMenu,
-        QApplication, QSize, QRectF, QWidget, QTreeView, QHBoxLayout, QVBoxLayout, QAbstractItemDelegate,
-        QGridLayout, QLabel, QRadioButton, QPushButton, QToolButton, QIcon, QEvent, sip, QKeyCombination)
+from qt.core import (
+    QAbstractItemDelegate,
+    QAbstractItemModel,
+    QAbstractItemView,
+    QApplication,
+    QEvent,
+    QFrame,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QItemSelectionModel,
+    QKeyCombination,
+    QKeySequence,
+    QLabel,
+    QMenu,
+    QModelIndex,
+    QObject,
+    QPushButton,
+    QRadioButton,
+    QRectF,
+    QSize,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTextDocument,
+    QToolButton,
+    QTreeView,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+    sip,
+)
 
-from calibre.utils.config import JSONConfig
+from calibre import prepare_string_for_xml, prints
 from calibre.constants import DEBUG
-from calibre import prints, prepare_string_for_xml
-from calibre.utils.icu import sort_key, lower
 from calibre.gui2 import error_dialog, info_dialog
-from calibre.utils.localization import pgettext
-from calibre.utils.search_query_parser import SearchQueryParser, ParseException
 from calibre.gui2.search_box import SearchBox2
+from calibre.utils.config import JSONConfig
+from calibre.utils.icu import lower, sort_key
+from calibre.utils.localization import pgettext
+from calibre.utils.search_query_parser import ParseException, SearchQueryParser
 from polyglot.builtins import iteritems, itervalues
 
 ROOT = QModelIndex()
diff --git a/src/calibre/gui2/languages.py b/src/calibre/gui2/languages.py
index 0da571560f..f859bb2867 100644
--- a/src/calibre/gui2/languages.py
+++ b/src/calibre/gui2/languages.py
@@ -6,10 +6,11 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from qt.core import QComboBox
+
 from calibre.gui2 import gui_prefs
 from calibre.gui2.complete2 import EditWithComplete
+from calibre.utils.icu import lower, sort_key
 from calibre.utils.localization import lang_map_for_ui
-from calibre.utils.icu import sort_key, lower
 from polyglot.builtins import iteritems, itervalues
 
 
diff --git a/src/calibre/gui2/layout.py b/src/calibre/gui2/layout.py
index c4a167f7cc..86b85ccfb7 100644
--- a/src/calibre/gui2/layout.py
+++ b/src/calibre/gui2/layout.py
@@ -6,9 +6,23 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from functools import partial
+
 from qt.core import (
-    QActionGroup, QCoreApplication, QFrame, QHBoxLayout, QIcon, QLabel, QLineEdit,
-    QMenu, QObject, QSizePolicy, Qt, QToolButton, QVBoxLayout, QWidget, pyqtSignal,
+    QActionGroup,
+    QCoreApplication,
+    QFrame,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QMenu,
+    QObject,
+    QSizePolicy,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import human_readable
diff --git a/src/calibre/gui2/layout_menu.py b/src/calibre/gui2/layout_menu.py
index 01c05720ba..75edc9f371 100644
--- a/src/calibre/gui2/layout_menu.py
+++ b/src/calibre/gui2/layout_menu.py
@@ -2,10 +2,7 @@
 # License: GPLv3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QFontMetrics, QHBoxLayout, QIcon, QMenu, QStylePainter, QPushButton, QSize,
-    QSizePolicy, Qt, QWidget, QStyleOption, QStyle)
-
+from qt.core import QFontMetrics, QHBoxLayout, QIcon, QMenu, QPushButton, QSize, QSizePolicy, QStyle, QStyleOption, QStylePainter, Qt, QWidget
 
 ICON_SZ = 64
 
diff --git a/src/calibre/gui2/library/alternate_views.py b/src/calibre/gui2/library/alternate_views.py
index cd0fee3c3a..69086f512d 100644
--- a/src/calibre/gui2/library/alternate_views.py
+++ b/src/calibre/gui2/library/alternate_views.py
@@ -5,25 +5,59 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import itertools
-from io import BytesIO
 import math
 import operator
 import os
 import weakref
 from collections import namedtuple
 from functools import wraps
-from PIL import Image
-from qt.core import (
-    QAbstractItemView, QApplication, QBuffer, QByteArray, QColor, QDrag, QEasingCurve,
-    QEvent, QFont, QHelpEvent, QIcon, QImage, QIODevice, QItemSelection,
-    QItemSelectionModel, QListView, QMimeData, QModelIndex, QPainter, QPalette, QPixmap,
-    QPoint, QPropertyAnimation, QRect, QSize, QStyledItemDelegate, QStyleOptionViewItem,
-    Qt, QTableView, QTimer, QToolTip, QTreeView, QUrl, pyqtProperty, pyqtSignal,
-    pyqtSlot, qBlue, qGreen, qRed,
-)
+from io import BytesIO
 from textwrap import wrap
 from threading import Event, Thread
 
+from PIL import Image
+from qt.core import (
+    QAbstractItemView,
+    QApplication,
+    QBuffer,
+    QByteArray,
+    QColor,
+    QDrag,
+    QEasingCurve,
+    QEvent,
+    QFont,
+    QHelpEvent,
+    QIcon,
+    QImage,
+    QIODevice,
+    QItemSelection,
+    QItemSelectionModel,
+    QListView,
+    QMimeData,
+    QModelIndex,
+    QPainter,
+    QPalette,
+    QPixmap,
+    QPoint,
+    QPropertyAnimation,
+    QRect,
+    QSize,
+    QStyledItemDelegate,
+    QStyleOptionViewItem,
+    Qt,
+    QTableView,
+    QTimer,
+    QToolTip,
+    QTreeView,
+    QUrl,
+    pyqtProperty,
+    pyqtSignal,
+    pyqtSlot,
+    qBlue,
+    qGreen,
+    qRed,
+)
+
 from calibre import fit_image, human_readable, prepare_string_for_xml
 from calibre.constants import DEBUG, config_dir, islinux
 from calibre.ebooks.metadata import fmt_sidx, rating_to_stars
diff --git a/src/calibre/gui2/library/annotations.py b/src/calibre/gui2/library/annotations.py
index 0a53a414c9..2ef18eb728 100644
--- a/src/calibre/gui2/library/annotations.py
+++ b/src/calibre/gui2/library/annotations.py
@@ -6,25 +6,45 @@ import json
 import os
 import re
 from functools import lru_cache, partial
-from qt.core import (
-    QAbstractItemView, QApplication, QCheckBox, QComboBox, QDateTime, QDialog,
-    QDialogButtonBox, QFont, QFormLayout, QFrame, QHBoxLayout, QIcon, QKeySequence,
-    QLabel, QLocale, QMenu, QPalette, QPlainTextEdit, QSize, QSplitter, Qt,
-    QTextBrowser, QTimer, QToolButton, QTreeWidget, QTreeWidgetItem, QVBoxLayout,
-    QWidget, pyqtSignal,
-)
 from urllib.parse import quote
 
-from calibre import prepare_string_for_xml
-from calibre.constants import (
-    builtin_colors_dark, builtin_colors_light, builtin_decorations,
+from qt.core import (
+    QAbstractItemView,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDateTime,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFormLayout,
+    QFrame,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QLocale,
+    QMenu,
+    QPalette,
+    QPlainTextEdit,
+    QSize,
+    QSplitter,
+    Qt,
+    QTextBrowser,
+    QTimer,
+    QToolButton,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
+
+from calibre import prepare_string_for_xml
+from calibre.constants import builtin_colors_dark, builtin_colors_light, builtin_decorations
 from calibre.db.backend import FTSQueryError
 from calibre.ebooks.metadata import authors_to_string, fmt_sidx
-from calibre.gui2 import (
-    Application, choose_save_file, config, error_dialog, gprefs, is_dark_theme,
-    safe_open_url,
-)
+from calibre.gui2 import Application, choose_save_file, config, error_dialog, gprefs, is_dark_theme, safe_open_url
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.viewer.widgets import ResultsDelegate, SearchBox
 from calibre.gui2.widgets import BusyCursor
diff --git a/src/calibre/gui2/library/caches.py b/src/calibre/gui2/library/caches.py
index 4fc79f7b11..9d85bb3508 100644
--- a/src/calibre/gui2/library/caches.py
+++ b/src/calibre/gui2/library/caches.py
@@ -4,8 +4,8 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from threading import Lock, current_thread
 from collections import OrderedDict
+from threading import Lock, current_thread
 
 from qt.core import QImage, QPixmap
 
diff --git a/src/calibre/gui2/library/delegates.py b/src/calibre/gui2/library/delegates.py
index a83465682d..39718265b7 100644
--- a/src/calibre/gui2/library/delegates.py
+++ b/src/calibre/gui2/library/delegates.py
@@ -8,12 +8,35 @@ __docformat__ = 'restructuredtext en'
 import os
 import sys
 from datetime import datetime
+
 from qt.core import (
-    QAbstractTextDocumentLayout, QApplication, QComboBox, QDate, QDateTime,
-    QDateTimeEdit, QDialog, QDoubleSpinBox, QEvent, QFont, QFontInfo, QIcon,
-    QKeySequence, QLineEdit, QLocale, QMenu, QPalette, QSize, QSpinBox, QStyle,
-    QStyledItemDelegate, QStyleOptionComboBox, QStyleOptionSpinBox,
-    QStyleOptionViewItem, Qt, QTextDocument, QUrl,
+    QAbstractTextDocumentLayout,
+    QApplication,
+    QComboBox,
+    QDate,
+    QDateTime,
+    QDateTimeEdit,
+    QDialog,
+    QDoubleSpinBox,
+    QEvent,
+    QFont,
+    QFontInfo,
+    QIcon,
+    QKeySequence,
+    QLineEdit,
+    QLocale,
+    QMenu,
+    QPalette,
+    QSize,
+    QSpinBox,
+    QStyle,
+    QStyledItemDelegate,
+    QStyleOptionComboBox,
+    QStyleOptionSpinBox,
+    QStyleOptionViewItem,
+    Qt,
+    QTextDocument,
+    QUrl,
 )
 
 from calibre.constants import iswindows
@@ -25,16 +48,11 @@ from calibre.gui2.dialogs.tag_editor import TagEditor
 from calibre.gui2.languages import LanguagesEdit
 from calibre.gui2.markdown_editor import MarkdownEditDialog
 from calibre.gui2.widgets import EnLineEdit
-from calibre.gui2.widgets2 import (
-    DateTimeEdit as DateTimeEditBase, RatingEditor,
-    populate_standard_spinbox_context_menu,
-)
+from calibre.gui2.widgets2 import DateTimeEdit as DateTimeEditBase
+from calibre.gui2.widgets2 import RatingEditor, populate_standard_spinbox_context_menu
 from calibre.library.comments import markdown
 from calibre.utils.config import tweaks
-from calibre.utils.date import (
-    format_date, internal_iso_format_string, is_date_undefined, now, qt_from_dt,
-    qt_to_dt,
-)
+from calibre.utils.date import format_date, internal_iso_format_string, is_date_undefined, now, qt_from_dt, qt_to_dt
 from calibre.utils.icu import sort_key
 
 
diff --git a/src/calibre/gui2/library/models.py b/src/calibre/gui2/library/models.py
index 77b99d2e6d..95d02f39c7 100644
--- a/src/calibre/gui2/library/models.py
+++ b/src/calibre/gui2/library/models.py
@@ -14,17 +14,11 @@ import time
 import traceback
 from collections import defaultdict, namedtuple
 from itertools import groupby
-from qt.core import (
-    QAbstractTableModel, QApplication, QColor, QFont, QFontMetrics, QIcon, QImage,
-    QModelIndex, QPainter, QPixmap, Qt, pyqtSignal,
-)
 
-from calibre import (
-    fit_image, human_readable, isbytestring, prepare_string_for_xml, strftime,
-)
-from calibre.constants import (
-    DEBUG, config_dir, dark_link_color, filesystem_encoding
-)
+from qt.core import QAbstractTableModel, QApplication, QColor, QFont, QFontMetrics, QIcon, QImage, QModelIndex, QPainter, QPixmap, Qt, pyqtSignal
+
+from calibre import fit_image, human_readable, isbytestring, prepare_string_for_xml, strftime
+from calibre.constants import DEBUG, config_dir, dark_link_color, filesystem_encoding
 from calibre.db.search import CONTAINS_MATCH, EQUALS_MATCH, REGEXP_MATCH, _match
 from calibre.db.utils import force_to_bool
 from calibre.ebooks.metadata import authors_to_string, fmt_sidx, string_to_authors
@@ -35,9 +29,7 @@ from calibre.library.coloring import color_row_key
 from calibre.library.save_to_disk import find_plugboard
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.utils.config import device_prefs, prefs, tweaks
-from calibre.utils.date import (
-    UNDEFINED_DATE, dt_factory, is_date_undefined, qt_from_dt, qt_to_dt,
-)
+from calibre.utils.date import UNDEFINED_DATE, dt_factory, is_date_undefined, qt_from_dt, qt_to_dt
 from calibre.utils.icu import sort_key
 from calibre.utils.localization import calibre_langcode_to_name, ngettext
 from calibre.utils.resources import get_path as P
diff --git a/src/calibre/gui2/library/notes.py b/src/calibre/gui2/library/notes.py
index 963b804f52..2988b17fa2 100644
--- a/src/calibre/gui2/library/notes.py
+++ b/src/calibre/gui2/library/notes.py
@@ -3,10 +3,29 @@
 
 import os
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QCheckBox, QDialog, QDialogButtonBox, QFont, QHBoxLayout, QIcon,
-    QKeySequence, QLabel, QMenu, QPushButton, QSize, QSplitter, Qt, QTimer, QToolButton,
-    QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QMenu,
+    QPushButton,
+    QSize,
+    QSplitter,
+    Qt,
+    QTimer,
+    QToolButton,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import sanitize_file_name
diff --git a/src/calibre/gui2/library/views.py b/src/calibre/gui2/library/views.py
index 99eb8f8184..2d60f4cdfb 100644
--- a/src/calibre/gui2/library/views.py
+++ b/src/calibre/gui2/library/views.py
@@ -9,29 +9,62 @@ import itertools
 import operator
 from collections import OrderedDict
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QDialog, QDialogButtonBox, QDrag, QEvent, QFont, QFontMetrics,
-    QGridLayout, QHeaderView, QIcon, QItemSelection, QItemSelectionModel, QLabel, QMenu,
-    QMimeData, QModelIndex, QPoint, QPushButton, QSize, QSpinBox, QStyle,
-    QStyleOptionHeader, Qt, QTableView, QTimer, QUrl, pyqtSignal,
+    QAbstractItemView,
+    QDialog,
+    QDialogButtonBox,
+    QDrag,
+    QEvent,
+    QFont,
+    QFontMetrics,
+    QGridLayout,
+    QHeaderView,
+    QIcon,
+    QItemSelection,
+    QItemSelectionModel,
+    QLabel,
+    QMenu,
+    QMimeData,
+    QModelIndex,
+    QPoint,
+    QPushButton,
+    QSize,
+    QSpinBox,
+    QStyle,
+    QStyleOptionHeader,
+    Qt,
+    QTableView,
+    QTimer,
+    QUrl,
+    pyqtSignal,
 )
 
 from calibre import force_unicode
 from calibre.constants import filesystem_encoding, islinux
-from calibre.gui2 import (
-    BOOK_DETAILS_DISPLAY_DEBOUNCE_DELAY, FunctionDispatcher, error_dialog, gprefs,
-)
+from calibre.gui2 import BOOK_DETAILS_DISPLAY_DEBOUNCE_DELAY, FunctionDispatcher, error_dialog, gprefs
 from calibre.gui2.dialogs.enum_values_edit import EnumValuesEdit
 from calibre.gui2.gestures import GestureManager
 from calibre.gui2.library import DEFAULT_SORT
-from calibre.gui2.library.alternate_views import (
-    AlternateViews, handle_enter_press, setup_dnd_interface,
-)
+from calibre.gui2.library.alternate_views import AlternateViews, handle_enter_press, setup_dnd_interface
 from calibre.gui2.library.delegates import (
-    CcBoolDelegate, CcCommentsDelegate, CcDateDelegate, CcEnumDelegate,
-    CcLongTextDelegate, CcMarkdownDelegate, CcNumberDelegate, CcSeriesDelegate,
-    CcTemplateDelegate, CcTextDelegate, CompleteDelegate, DateDelegate,
-    LanguagesDelegate, PubDateDelegate, RatingDelegate, SeriesDelegate, TextDelegate,
+    CcBoolDelegate,
+    CcCommentsDelegate,
+    CcDateDelegate,
+    CcEnumDelegate,
+    CcLongTextDelegate,
+    CcMarkdownDelegate,
+    CcNumberDelegate,
+    CcSeriesDelegate,
+    CcTemplateDelegate,
+    CcTextDelegate,
+    CompleteDelegate,
+    DateDelegate,
+    LanguagesDelegate,
+    PubDateDelegate,
+    RatingDelegate,
+    SeriesDelegate,
+    TextDelegate,
 )
 from calibre.gui2.library.models import BooksModel, DeviceBooksModel
 from calibre.gui2.pin_columns import PinTableView
diff --git a/src/calibre/gui2/listener.py b/src/calibre/gui2/listener.py
index 557165c83b..babf5a0f56 100644
--- a/src/calibre/gui2/listener.py
+++ b/src/calibre/gui2/listener.py
@@ -7,9 +7,8 @@ import socket
 from contextlib import closing
 from functools import partial
 from itertools import count
-from qt.core import (
-    QAbstractSocket, QByteArray, QLocalServer, QLocalSocket, pyqtSignal
-)
+
+from qt.core import QAbstractSocket, QByteArray, QLocalServer, QLocalSocket, pyqtSignal
 
 from calibre.utils.ipc import gui_socket_address
 
diff --git a/src/calibre/gui2/lrf_renderer/document.py b/src/calibre/gui2/lrf_renderer/document.py
index 54a80a59ac..bd65174ccc 100644
--- a/src/calibre/gui2/lrf_renderer/document.py
+++ b/src/calibre/gui2/lrf_renderer/document.py
@@ -4,12 +4,11 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import collections
 import glob
 import itertools
-from qt.core import (
-    QBrush, QByteArray, QColor, QFontDatabase, QGraphicsItem, QGraphicsLineItem,
-    QGraphicsRectItem, QGraphicsScene, QPen, Qt, pyqtSignal,
-)
 
-from calibre.ebooks.lrf.objects import Canvas as __Canvas, RuledLine as _RuledLine
+from qt.core import QBrush, QByteArray, QColor, QFontDatabase, QGraphicsItem, QGraphicsLineItem, QGraphicsRectItem, QGraphicsScene, QPen, Qt, pyqtSignal
+
+from calibre.ebooks.lrf.objects import Canvas as __Canvas
+from calibre.ebooks.lrf.objects import RuledLine as _RuledLine
 from calibre.gui2.lrf_renderer.text import COLOR, FontLoader, PixmapItem, TextBlock
 from calibre.utils.resources import get_path as P
 
diff --git a/src/calibre/gui2/lrf_renderer/main.py b/src/calibre/gui2/lrf_renderer/main.py
index b3fb4405b2..15af0abb16 100644
--- a/src/calibre/gui2/lrf_renderer/main.py
+++ b/src/calibre/gui2/lrf_renderer/main.py
@@ -1,23 +1,22 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import sys, logging, os, traceback, time
+import logging
+import os
+import sys
+import time
+import traceback
 
-from qt.core import (
-    QKeySequence, QPainter, QDialog, QSpinBox, QSlider, QIcon, Qt, QCoreApplication, QThread, QScrollBar)
+from qt.core import QCoreApplication, QDialog, QIcon, QKeySequence, QPainter, QScrollBar, QSlider, QSpinBox, Qt, QThread
 
-from calibre import __appname__, setup_cli_handlers, islinux, isbsd, as_unicode
-from calibre.gui2 import gprefs
+from calibre import __appname__, as_unicode, isbsd, islinux, setup_cli_handlers
 from calibre.ebooks.lrf.lrfparser import LRFDocument
-
-from calibre.gui2 import (
-        error_dialog, choose_files, Application
-        )
+from calibre.gui2 import Application, choose_files, error_dialog, gprefs
 from calibre.gui2.dialogs.conversion_error import ConversionErrorDialog
-from calibre.gui2.lrf_renderer.main_ui import Ui_MainWindow
 from calibre.gui2.lrf_renderer.config_ui import Ui_ViewerConfig
-from calibre.gui2.main_window import MainWindow
 from calibre.gui2.lrf_renderer.document import Document
+from calibre.gui2.lrf_renderer.main_ui import Ui_MainWindow
+from calibre.gui2.main_window import MainWindow
 from calibre.gui2.search_box import SearchBox2
 
 
diff --git a/src/calibre/gui2/lrf_renderer/text.py b/src/calibre/gui2/lrf_renderer/text.py
index 3c553079ad..53ab890a58 100644
--- a/src/calibre/gui2/lrf_renderer/text.py
+++ b/src/calibre/gui2/lrf_renderer/text.py
@@ -1,16 +1,20 @@
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import sys, collections, operator, copy, re, numbers
+import collections
+import copy
+import numbers
+import operator
+import re
+import sys
 
-from qt.core import (
-    Qt, QRectF, QFont, QColor, QPixmap, QGraphicsPixmapItem, QGraphicsItem,
-    QFontMetrics, QPen, QBrush, QGraphicsRectItem)
+from qt.core import QBrush, QColor, QFont, QFontMetrics, QGraphicsItem, QGraphicsPixmapItem, QGraphicsRectItem, QPen, QPixmap, QRectF, Qt
 
-from calibre.ebooks.lrf.fonts import LIBERATION_FONT_MAP
 from calibre.ebooks.hyphenate import hyphenate_word
+from calibre.ebooks.lrf.fonts import LIBERATION_FONT_MAP
 from polyglot.builtins import string_or_bytes
 
+
 def WEIGHT_MAP(wt):
     return int(wt / 10 - 1)
 def NULL(a, b):
diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index 54f849fc0f..5b3966c35a 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -2,23 +2,18 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import apsw
 import os
 import re
 import sys
 import time
 import traceback
+
+import apsw
 from qt.core import QCoreApplication, QIcon, QObject, QTimer
 
 from calibre import force_unicode, prints
-from calibre.constants import (
-    DEBUG, MAIN_APP_UID, __appname__, filesystem_encoding, get_portable_base, islinux,
-    ismacos, iswindows,
-)
-from calibre.gui2 import (
-    Application, choose_dir, error_dialog, gprefs, initialize_file_icon_provider,
-    question_dialog, setup_gui_option_parser, timed_print,
-)
+from calibre.constants import DEBUG, MAIN_APP_UID, __appname__, filesystem_encoding, get_portable_base, islinux, ismacos, iswindows
+from calibre.gui2 import Application, choose_dir, error_dialog, gprefs, initialize_file_icon_provider, question_dialog, setup_gui_option_parser, timed_print
 from calibre.gui2.listener import send_message_in_process
 from calibre.gui2.main_window import option_parser as _option_parser
 from calibre.gui2.splash_screen import SplashScreen
diff --git a/src/calibre/gui2/main_window.py b/src/calibre/gui2/main_window.py
index e6e8e8798a..fae1b3f9d3 100644
--- a/src/calibre/gui2/main_window.py
+++ b/src/calibre/gui2/main_window.py
@@ -2,13 +2,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 
-import gc, os
+import gc
+import os
 import sys
 import weakref
-from qt.core import (
-    QAction, QIcon, QKeySequence, QMainWindow, QMenu, QMenuBar, QObject, Qt, QTimer,
-    pyqtSignal
-)
+
+from qt.core import QAction, QIcon, QKeySequence, QMainWindow, QMenu, QMenuBar, QObject, Qt, QTimer, pyqtSignal
 
 from calibre import as_unicode, prepare_string_for_xml, prints
 from calibre.constants import iswindows
@@ -137,8 +136,9 @@ class MainWindow(QMainWindow):
     def show_possible_sharing_violation(self, e: Exception, det_msg: str = '') -> bool:
         if not iswindows or not isinstance(e, OSError):
             return False
-        from calibre_extensions import winutil
         import errno
+
+        from calibre_extensions import winutil
         if not (e.winerror == winutil.ERROR_SHARING_VIOLATION or e.errno == errno.EACCES or isinstance(e, PermissionError)):
             return False
         msg = getattr(e, 'locking_violation_msg', '')
diff --git a/src/calibre/gui2/markdown_editor.py b/src/calibre/gui2/markdown_editor.py
index 3d101cd8b2..52ff74fa28 100644
--- a/src/calibre/gui2/markdown_editor.py
+++ b/src/calibre/gui2/markdown_editor.py
@@ -2,12 +2,10 @@
 # License: GPLv3 Copyright: 2023, un_pogaz <un.pogaz@gmail.com>
 
 import os
-from qt.core import (
-    QDialog, QDialogButtonBox, QPlainTextEdit, QSize, Qt, QTabWidget, QUrl,
-    QVBoxLayout, QWidget, pyqtSignal,
-)
 
-from calibre.gui2 import safe_open_url, gprefs
+from qt.core import QDialog, QDialogButtonBox, QPlainTextEdit, QSize, Qt, QTabWidget, QUrl, QVBoxLayout, QWidget, pyqtSignal
+
+from calibre.gui2 import gprefs, safe_open_url
 from calibre.gui2.book_details import resolved_css
 from calibre.gui2.widgets2 import HTMLDisplay
 from calibre.library.comments import markdown as get_markdown
diff --git a/src/calibre/gui2/markdown_syntax_highlighter.py b/src/calibre/gui2/markdown_syntax_highlighter.py
index 693f43d6b9..aef2ef48f3 100644
--- a/src/calibre/gui2/markdown_syntax_highlighter.py
+++ b/src/calibre/gui2/markdown_syntax_highlighter.py
@@ -3,10 +3,8 @@
 
 
 import re
-from qt.core import (
-    QApplication, QBrush, QColor, QFont, QSyntaxHighlighter, QTextCharFormat,
-    QTextCursor, QTextLayout,
-)
+
+from qt.core import QApplication, QBrush, QColor, QFont, QSyntaxHighlighter, QTextCharFormat, QTextCursor, QTextLayout
 
 from calibre.gui2.palette import dark_link_color, light_link_color
 
diff --git a/src/calibre/gui2/metadata/basic_widgets.py b/src/calibre/gui2/metadata/basic_widgets.py
index c7ee6ecc80..74d2f13973 100644
--- a/src/calibre/gui2/metadata/basic_widgets.py
+++ b/src/calibre/gui2/metadata/basic_widgets.py
@@ -11,11 +11,35 @@ import shutil
 import textwrap
 import weakref
 from datetime import date, datetime
+
 from qt.core import (
-    QAbstractItemView, QAction, QApplication, QComboBox, QDateTime, QDialog,
-    QDialogButtonBox, QDoubleSpinBox, QGridLayout, QIcon, QKeySequence, QLabel,
-    QLineEdit, QListWidgetItem, QMenu, QMessageBox, QPixmap, QPlainTextEdit, QSize,
-    QSizePolicy, Qt, QToolButton, QUndoCommand, QUndoStack, QUrl, QVBoxLayout, QWidget,
+    QAbstractItemView,
+    QAction,
+    QApplication,
+    QComboBox,
+    QDateTime,
+    QDialog,
+    QDialogButtonBox,
+    QDoubleSpinBox,
+    QGridLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QLineEdit,
+    QListWidgetItem,
+    QMenu,
+    QMessageBox,
+    QPixmap,
+    QPlainTextEdit,
+    QSize,
+    QSizePolicy,
+    Qt,
+    QToolButton,
+    QUndoCommand,
+    QUndoStack,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
     pyqtSignal,
 )
 
@@ -24,31 +48,29 @@ from calibre.constants import iswindows
 from calibre.customize.ui import run_plugins_on_import
 from calibre.db import SPOOL_SIZE
 from calibre.ebooks import BOOK_EXTENSIONS
-from calibre.ebooks.metadata import (
-    authors_to_sort_string, check_isbn, string_to_authors, title_sort,
-)
+from calibre.ebooks.metadata import authors_to_sort_string, check_isbn, string_to_authors, title_sort
 from calibre.ebooks.metadata.meta import get_metadata
-from calibre.gui2 import (
-    choose_files_and_remember_all_files, choose_images, error_dialog,
-    file_icon_provider, gprefs,
-)
+from calibre.gui2 import choose_files_and_remember_all_files, choose_images, error_dialog, file_icon_provider, gprefs
 from calibre.gui2.comments_editor import Editor
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.gui2.dialogs.tag_editor import TagEditor
 from calibre.gui2.languages import LanguagesEdit as LE
-from calibre.gui2.widgets import (
-    EnLineEdit, FormatList as _FormatList, ImageView, LineEditIndicators,
-)
-from calibre.gui2.widgets2 import (
-    DateTimeEdit, Dialog, RatingEditor, RightClickButton, access_key,
-    populate_standard_spinbox_context_menu,
-)
+from calibre.gui2.widgets import EnLineEdit, ImageView, LineEditIndicators
+from calibre.gui2.widgets import FormatList as _FormatList
+from calibre.gui2.widgets2 import DateTimeEdit, Dialog, RatingEditor, RightClickButton, access_key, populate_standard_spinbox_context_menu
 from calibre.library.comments import comments_to_html
 from calibre.ptempfile import PersistentTemporaryFile, SpooledTemporaryFile
 from calibre.utils.config import prefs, tweaks
 from calibre.utils.date import (
-    UNDEFINED_DATE, as_local_time, internal_iso_format_string, is_date_undefined,
-    local_tz, parse_only_date, qt_from_dt, qt_to_dt, utcfromtimestamp,
+    UNDEFINED_DATE,
+    as_local_time,
+    internal_iso_format_string,
+    is_date_undefined,
+    local_tz,
+    parse_only_date,
+    qt_from_dt,
+    qt_to_dt,
+    utcfromtimestamp,
 )
 from calibre.utils.filenames import make_long_path_useable
 from calibre.utils.icu import sort_key, strcmp
@@ -1252,9 +1274,7 @@ class Cover(ImageView):  # {{{
         cdata = self.current_val
         if not cdata:
             return
-        from calibre.utils.img import (
-            image_from_data, image_to_data, remove_borders_from_image,
-        )
+        from calibre.utils.img import image_from_data, image_to_data, remove_borders_from_image
         img = image_from_data(cdata)
         nimg = remove_borders_from_image(img)
         if nimg is not img:
diff --git a/src/calibre/gui2/metadata/bulk_download.py b/src/calibre/gui2/metadata/bulk_download.py
index b744635ce9..e238aad475 100644
--- a/src/calibre/gui2/metadata/bulk_download.py
+++ b/src/calibre/gui2/metadata/bulk_download.py
@@ -8,9 +8,10 @@ __docformat__ = 'restructuredtext en'
 import os
 import shutil
 import time
-from qt.core import QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, Qt
 from threading import Thread
 
+from qt.core import QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, Qt
+
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
 from calibre.gui2.threaded_jobs import ThreadedJob
 from calibre.ptempfile import PersistentTemporaryDirectory, PersistentTemporaryFile
diff --git a/src/calibre/gui2/metadata/config.py b/src/calibre/gui2/metadata/config.py
index 67c99c1d7e..846c360432 100644
--- a/src/calibre/gui2/metadata/config.py
+++ b/src/calibre/gui2/metadata/config.py
@@ -7,10 +7,8 @@ __docformat__ = 'restructuredtext en'
 
 import numbers
 import textwrap
-from qt.core import (
-    QCheckBox, QComboBox, QDoubleSpinBox, QGridLayout, QGroupBox, QLabel, QLineEdit,
-    QListView, QSpinBox, Qt, QVBoxLayout, QWidget
-)
+
+from qt.core import QCheckBox, QComboBox, QDoubleSpinBox, QGridLayout, QGroupBox, QLabel, QLineEdit, QListView, QSpinBox, Qt, QVBoxLayout, QWidget
 
 from calibre.gui2.preferences.metadata_sources import FieldsModel as FM
 from calibre.utils.icu import sort_key
diff --git a/src/calibre/gui2/metadata/diff.py b/src/calibre/gui2/metadata/diff.py
index e9c9f4b872..fcf279b6cc 100644
--- a/src/calibre/gui2/metadata/diff.py
+++ b/src/calibre/gui2/metadata/diff.py
@@ -8,11 +8,33 @@ import os
 import weakref
 from collections import OrderedDict, namedtuple
 from functools import partial
+
 from qt.core import (
-    QAction, QApplication, QCheckBox, QColor, QDialog, QDialogButtonBox, QFont,
-    QGridLayout, QHBoxLayout, QIcon, QKeySequence, QLabel, QMenu, QPainter, QPen,
-    QPixmap, QScrollArea, QSize, QSizePolicy, QStackedLayout, Qt, QToolButton,
-    QVBoxLayout, QWidget, pyqtSignal,
+    QAction,
+    QApplication,
+    QCheckBox,
+    QColor,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QMenu,
+    QPainter,
+    QPen,
+    QPixmap,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QStackedLayout,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import fit_image
diff --git a/src/calibre/gui2/metadata/pdf_covers.py b/src/calibre/gui2/metadata/pdf_covers.py
index 3c6078734a..721d297290 100644
--- a/src/calibre/gui2/metadata/pdf_covers.py
+++ b/src/calibre/gui2/metadata/pdf_covers.py
@@ -8,13 +8,27 @@ __docformat__ = 'restructuredtext en'
 import os
 import shutil
 import sys
-from qt.core import (
-    QAbstractItemView, QApplication, QDialog, QDialogButtonBox, QLabel, QListView,
-    QListWidget, QListWidgetItem, QPixmap, QSize, QStyledItemDelegate, Qt, QTimer,
-    QVBoxLayout, pyqtSignal, sip,
-)
 from threading import Thread
 
+from qt.core import (
+    QAbstractItemView,
+    QApplication,
+    QDialog,
+    QDialogButtonBox,
+    QLabel,
+    QListView,
+    QListWidget,
+    QListWidgetItem,
+    QPixmap,
+    QSize,
+    QStyledItemDelegate,
+    Qt,
+    QTimer,
+    QVBoxLayout,
+    pyqtSignal,
+    sip,
+)
+
 from calibre import as_unicode
 from calibre.ebooks.metadata.archive import get_comic_images
 from calibre.ebooks.metadata.pdf import page_images
diff --git a/src/calibre/gui2/metadata/single.py b/src/calibre/gui2/metadata/single.py
index ceaa5efbdb..940e16ea5d 100644
--- a/src/calibre/gui2/metadata/single.py
+++ b/src/calibre/gui2/metadata/single.py
@@ -8,25 +8,58 @@ __docformat__ = 'restructuredtext en'
 import os
 from datetime import datetime
 from functools import partial
+
 from qt.core import (
-    QDialog, QDialogButtonBox, QFrame, QGridLayout, QGroupBox, QHBoxLayout, QIcon,
-    QInputDialog, QKeySequence, QMenu, QPushButton, QScrollArea, QShortcut, QSize,
-    QSizePolicy, QSpacerItem, QSplitter, Qt, QTabWidget, QToolButton, QVBoxLayout,
-    QWidget, pyqtSignal,
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QGridLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QKeySequence,
+    QMenu,
+    QPushButton,
+    QScrollArea,
+    QShortcut,
+    QSize,
+    QSizePolicy,
+    QSpacerItem,
+    QSplitter,
+    Qt,
+    QTabWidget,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.constants import ismacos
 from calibre.ebooks.metadata import authors_to_string, string_to_authors
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.gui2 import error_dialog, gprefs, pixmap_to_data
-from calibre.gui2.custom_column_widgets import (
-    Comments, populate_metadata_page, get_custom_columns_to_display_in_editor)
+from calibre.gui2.custom_column_widgets import Comments, get_custom_columns_to_display_in_editor, populate_metadata_page
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.metadata.basic_widgets import (
-    AuthorsEdit, AuthorSortEdit, BuddyLabel, CommentsEdit, Cover, DateEdit,
-    FormatsManager, IdentifiersEdit, LanguagesEdit, PubdateEdit, PublisherEdit,
-    RatingEdit, RightClickButton, SeriesEdit, SeriesIndexEdit, TagsEdit, TitleEdit,
-    TitleSortEdit
+    AuthorsEdit,
+    AuthorSortEdit,
+    BuddyLabel,
+    CommentsEdit,
+    Cover,
+    DateEdit,
+    FormatsManager,
+    IdentifiersEdit,
+    LanguagesEdit,
+    PubdateEdit,
+    PublisherEdit,
+    RatingEdit,
+    RightClickButton,
+    SeriesEdit,
+    SeriesIndexEdit,
+    TagsEdit,
+    TitleEdit,
+    TitleSortEdit,
 )
 from calibre.gui2.metadata.single_download import FullFetch
 from calibre.gui2.widgets2 import CenteredToolButton
diff --git a/src/calibre/gui2/metadata/single_download.py b/src/calibre/gui2/metadata/single_download.py
index efc8916fb9..955125dfc2 100644
--- a/src/calibre/gui2/metadata/single_download.py
+++ b/src/calibre/gui2/metadata/single_download.py
@@ -12,16 +12,46 @@ import os
 import time
 from io import BytesIO
 from operator import attrgetter
-from qt.core import (
-    QAbstractItemView, QAbstractListModel, QAbstractTableModel, QApplication, QCursor,
-    QDialog, QDialogButtonBox, QGridLayout, QHBoxLayout, QIcon, QItemSelectionModel,
-    QLabel, QListView, QMenu, QModelIndex, QPalette, QPixmap, QPushButton, QRect,
-    QRectF, QSize, QSizePolicy, QSplitter, QStackedWidget, QStringListModel, QStyle,
-    QStyledItemDelegate, Qt, QTableView, QTextBrowser, QTextDocument, QTimer,
-    QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Event, Thread
 
+from qt.core import (
+    QAbstractItemView,
+    QAbstractListModel,
+    QAbstractTableModel,
+    QApplication,
+    QCursor,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QItemSelectionModel,
+    QLabel,
+    QListView,
+    QMenu,
+    QModelIndex,
+    QPalette,
+    QPixmap,
+    QPushButton,
+    QRect,
+    QRectF,
+    QSize,
+    QSizePolicy,
+    QSplitter,
+    QStackedWidget,
+    QStringListModel,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTableView,
+    QTextBrowser,
+    QTextDocument,
+    QTimer,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import force_unicode
 from calibre.customize.ui import metadata_plugins
 from calibre.db.constants import COVER_FILE_NAME, DATA_DIR_NAME
@@ -29,9 +59,7 @@ from calibre.ebooks.metadata import authors_to_string, rating_to_stars
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.opf2 import OPF
 from calibre.ebooks.metadata.sources.identify import urls_from_identifiers
-from calibre.gui2 import (
-    choose_save_file, error_dialog, gprefs, rating_font,
-)
+from calibre.gui2 import choose_save_file, error_dialog, gprefs, rating_font
 from calibre.gui2.progress_indicator import SpinAnimator
 from calibre.gui2.widgets2 import HTMLDisplay
 from calibre.library.comments import comments_to_html
diff --git a/src/calibre/gui2/open_with.py b/src/calibre/gui2/open_with.py
index 971da327cf..3d45ee233c 100644
--- a/src/calibre/gui2/open_with.py
+++ b/src/calibre/gui2/open_with.py
@@ -8,19 +8,32 @@ import os
 import uuid
 from contextlib import suppress
 from functools import partial
-from qt.core import (
-    QAction, QBuffer, QByteArray, QDialogButtonBox, QIcon, QInputDialog, QIODevice,
-    QKeySequence, QLabel, QListWidget, QListWidgetItem, QPixmap, QSize, QStackedLayout,
-    Qt, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 
+from qt.core import (
+    QAction,
+    QBuffer,
+    QByteArray,
+    QDialogButtonBox,
+    QIcon,
+    QInputDialog,
+    QIODevice,
+    QKeySequence,
+    QLabel,
+    QListWidget,
+    QListWidgetItem,
+    QPixmap,
+    QSize,
+    QStackedLayout,
+    Qt,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import as_unicode
 from calibre.constants import ismacos, iswindows
-from calibre.gui2 import (
-    Application, choose_files, choose_images, choose_osx_app, elided_text, error_dialog,
-    sanitize_env_vars,
-)
+from calibre.gui2 import Application, choose_files, choose_images, choose_osx_app, elided_text, error_dialog, sanitize_env_vars
 from calibre.gui2.progress_indicator import ProgressIndicator
 from calibre.gui2.widgets2 import Dialog
 from calibre.utils.config import JSONConfig
@@ -80,9 +93,7 @@ if iswindows:
     # Windows {{{
     import subprocess
 
-    from calibre.utils.open_with.windows import (
-        load_icon_for_cmdline, load_icon_resource,
-    )
+    from calibre.utils.open_with.windows import load_icon_for_cmdline, load_icon_resource
     from calibre.utils.winreg.default_programs import find_programs, friendly_app_name
     from calibre_extensions import winutil
     oprefs = JSONConfig('windows_open_with')
@@ -174,9 +185,7 @@ if iswindows:
 elif ismacos:
     # macOS {{{
     oprefs = JSONConfig('osx_open_with')
-    from calibre.utils.open_with.osx import (
-        entry_to_cmdline, find_programs, get_bundle_data, get_icon,
-    )
+    from calibre.utils.open_with.osx import entry_to_cmdline, find_programs, get_bundle_data, get_icon
 
     def entry_sort_key(entry):
         return sort_key(entry.get('name') or '')
@@ -224,9 +233,7 @@ elif ismacos:
 else:
     # XDG {{{
     oprefs = JSONConfig('xdg_open_with')
-    from calibre.utils.open_with.linux import (
-        entry_sort_key, entry_to_cmdline, find_programs,
-    )
+    from calibre.utils.open_with.linux import entry_sort_key, entry_to_cmdline, find_programs
 
     def change_name_in_entry(entry, newname):
         entry['Name'] = newname
diff --git a/src/calibre/gui2/palette.py b/src/calibre/gui2/palette.py
index 92a4af8896..00ebc471fa 100644
--- a/src/calibre/gui2/palette.py
+++ b/src/calibre/gui2/palette.py
@@ -5,10 +5,8 @@ import os
 import sys
 from contextlib import contextmanager, suppress
 from functools import lru_cache
-from qt.core import (
-    QApplication, QByteArray, QColor, QDataStream, QIcon, QIODeviceBase, QObject,
-    QPalette, QProxyStyle, QStyle, Qt,
-)
+
+from qt.core import QApplication, QByteArray, QColor, QDataStream, QIcon, QIODeviceBase, QObject, QPalette, QProxyStyle, QStyle, Qt
 
 from calibre.constants import DEBUG, dark_link_color, ismacos, iswindows
 
diff --git a/src/calibre/gui2/pin_columns.py b/src/calibre/gui2/pin_columns.py
index f7da595886..28f6b183fb 100644
--- a/src/calibre/gui2/pin_columns.py
+++ b/src/calibre/gui2/pin_columns.py
@@ -2,10 +2,10 @@
 # License: GPLv3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import QTableView, QSplitter
+from qt.core import QSplitter, QTableView
 
-from calibre.gui2.library import DEFAULT_SORT
 from calibre.gui2 import gprefs
+from calibre.gui2.library import DEFAULT_SORT
 
 
 class PinTableView(QTableView):
diff --git a/src/calibre/gui2/preferences/__init__.py b/src/calibre/gui2/preferences/__init__.py
index 57324e59f9..40a6d1a1a8 100644
--- a/src/calibre/gui2/preferences/__init__.py
+++ b/src/calibre/gui2/preferences/__init__.py
@@ -7,14 +7,29 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from qt.core import (QWidget, pyqtSignal, QCheckBox, QAbstractSpinBox, QApplication,
-    QLineEdit, QComboBox, Qt, QIcon, QDialog, QVBoxLayout,
-    QDialogButtonBox, QListView, QEvent, QListWidget, QTableWidget)
+from qt.core import (
+    QAbstractSpinBox,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QEvent,
+    QIcon,
+    QLineEdit,
+    QListView,
+    QListWidget,
+    Qt,
+    QTableWidget,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
 
 from calibre.customize.ui import preferences_plugins
-from calibre.utils.config import ConfigProxy
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.gui2.widgets import HistoryLineEdit
+from calibre.utils.config import ConfigProxy
 from polyglot.builtins import string_or_bytes
 
 
@@ -337,8 +352,8 @@ class ConfigDialog(QDialog):
 
 
 def init_gui():
-    from calibre.gui2.ui import Main
     from calibre.gui2.main import option_parser
+    from calibre.gui2.ui import Main
     from calibre.library import db
     parser = option_parser()
     opts, args = parser.parse_args([])
diff --git a/src/calibre/gui2/preferences/adding.py b/src/calibre/gui2/preferences/adding.py
index ee1235491e..5170ca613e 100644
--- a/src/calibre/gui2/preferences/adding.py
+++ b/src/calibre/gui2/preferences/adding.py
@@ -7,15 +7,14 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from qt.core import Qt, QVBoxLayout, QFormLayout, QDialog
+from qt.core import QDialog, QFormLayout, Qt, QVBoxLayout
 
-from calibre.gui2.preferences import ConfigWidgetBase, test_widget, \
-    CommaSeparatedList, AbortCommit
-from calibre.gui2.preferences.adding_ui import Ui_Form
-from calibre.utils.config import prefs
-from calibre.gui2.widgets import FilenamePattern
+from calibre.gui2 import choose_dir, error_dialog, gprefs, question_dialog
 from calibre.gui2.auto_add import AUTO_ADDED
-from calibre.gui2 import gprefs, choose_dir, error_dialog, question_dialog
+from calibre.gui2.preferences import AbortCommit, CommaSeparatedList, ConfigWidgetBase, test_widget
+from calibre.gui2.preferences.adding_ui import Ui_Form
+from calibre.gui2.widgets import FilenamePattern
+from calibre.utils.config import prefs
 
 
 class ConfigWidget(ConfigWidgetBase, Ui_Form):
diff --git a/src/calibre/gui2/preferences/behavior.py b/src/calibre/gui2/preferences/behavior.py
index 15d38ed0a8..ba758ca7d2 100644
--- a/src/calibre/gui2/preferences/behavior.py
+++ b/src/calibre/gui2/preferences/behavior.py
@@ -8,17 +8,17 @@ __docformat__ = 'restructuredtext en'
 import re
 from functools import partial
 
-from qt.core import Qt, QListWidgetItem
+from qt.core import QListWidgetItem, Qt
 
-from calibre.gui2.actions.choose_library import get_change_library_action_plugin
-from calibre.gui2.preferences import ConfigWidgetBase, test_widget, Setting
-from calibre.gui2.preferences.behavior_ui import Ui_Form
-from calibre.gui2 import config, info_dialog, dynamic, gprefs
-from calibre.utils.config import prefs
-from calibre.customize.ui import available_output_formats, all_input_formats
+from calibre.constants import iswindows
+from calibre.customize.ui import all_input_formats, available_output_formats
 from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.ebooks.oeb.iterator import is_supported
-from calibre.constants import iswindows
+from calibre.gui2 import config, dynamic, gprefs, info_dialog
+from calibre.gui2.actions.choose_library import get_change_library_action_plugin
+from calibre.gui2.preferences import ConfigWidgetBase, Setting, test_widget
+from calibre.gui2.preferences.behavior_ui import Ui_Form
+from calibre.utils.config import prefs
 from calibre.utils.icu import sort_key
 
 
diff --git a/src/calibre/gui2/preferences/coloring.py b/src/calibre/gui2/preferences/coloring.py
index 76544c7a35..fd7a9cb32d 100644
--- a/src/calibre/gui2/preferences/coloring.py
+++ b/src/calibre/gui2/preferences/coloring.py
@@ -9,28 +9,50 @@ import json
 import os
 import textwrap
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QAbstractListModel, QApplication, QCheckBox, QComboBox, QDialog,
-    QDialogButtonBox, QDoubleValidator, QFrame, QGridLayout, QIcon, QIntValidator,
-    QItemSelection, QItemSelectionModel, QLabel, QLineEdit, QListView, QListWidget,
-    QListWidgetItem, QPalette, QPushButton, QScrollArea, QSize, QSizePolicy,
-    QSpacerItem, QStandardItem, QStandardItemModel, Qt, QToolButton, QVBoxLayout,
-    QWidget, pyqtSignal,
+    QAbstractItemView,
+    QAbstractListModel,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QDoubleValidator,
+    QFrame,
+    QGridLayout,
+    QIcon,
+    QIntValidator,
+    QItemSelection,
+    QItemSelectionModel,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QListWidget,
+    QListWidgetItem,
+    QPalette,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QSpacerItem,
+    QStandardItem,
+    QStandardItemModel,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import as_unicode, prepare_string_for_xml, sanitize_file_name
 from calibre.constants import config_dir
-from calibre.gui2 import (
-    choose_files, choose_save_file, error_dialog, gprefs, open_local_file,
-    pixmap_to_data, question_dialog,
-)
+from calibre.gui2 import choose_files, choose_save_file, error_dialog, gprefs, open_local_file, pixmap_to_data, question_dialog
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
 from calibre.gui2.metadata.single_download import RichTextDelegate
 from calibre.gui2.preferences import ListViewWithMoveByKeyPress
 from calibre.gui2.widgets2 import ColorButton, FlowLayout, Separator
-from calibre.library.coloring import (
-    Rule, color_row_key, conditionable_columns, displayable_columns, rule_from_template,
-)
+from calibre.library.coloring import Rule, color_row_key, conditionable_columns, displayable_columns, rule_from_template
 from calibre.utils.icu import lower, sort_key
 from calibre.utils.localization import lang_map, ngettext
 from polyglot.builtins import iteritems
diff --git a/src/calibre/gui2/preferences/columns.py b/src/calibre/gui2/preferences/columns.py
index a145b6e6a5..eb27a61863 100644
--- a/src/calibre/gui2/preferences/columns.py
+++ b/src/calibre/gui2/preferences/columns.py
@@ -5,16 +5,16 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import copy, sys
+import copy
+import sys
 from contextlib import suppress
 
-from qt.core import Qt, QTableWidgetItem, QIcon, QAbstractItemView
+from qt.core import QAbstractItemView, QIcon, Qt, QTableWidgetItem
 
-from calibre.gui2 import gprefs, Application
+from calibre.gui2 import Application, error_dialog, gprefs, question_dialog
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget
 from calibre.gui2.preferences.columns_ui import Ui_Form
 from calibre.gui2.preferences.create_custom_column import CreateCustomColumn
-from calibre.gui2 import error_dialog, question_dialog
 
 
 class ConfigWidget(ConfigWidgetBase, Ui_Form):
diff --git a/src/calibre/gui2/preferences/conversion.py b/src/calibre/gui2/preferences/conversion.py
index 91ecbf0ae4..3bab6fb70a 100644
--- a/src/calibre/gui2/preferences/conversion.py
+++ b/src/calibre/gui2/preferences/conversion.py
@@ -7,21 +7,19 @@ __docformat__ = 'restructuredtext en'
 
 import importlib
 
-from qt.core import (
-    QIcon, Qt, QStringListModel, QListView, QSizePolicy, QHBoxLayout, QSize,
-    QStackedWidget, pyqtSignal, QScrollArea)
+from qt.core import QHBoxLayout, QIcon, QListView, QScrollArea, QSize, QSizePolicy, QStackedWidget, QStringListModel, Qt, pyqtSignal
 
-from calibre.gui2.preferences import ConfigWidgetBase, test_widget, AbortCommit
+from calibre.customize.ui import input_format_plugins, output_format_plugins
 from calibre.ebooks.conversion.plumber import Plumber
-from calibre.utils.logging import Log
-from calibre.gui2.convert.look_and_feel import LookAndFeelWidget
+from calibre.gui2.convert import config_widget_for_input_plugin
 from calibre.gui2.convert.heuristics import HeuristicsWidget
-from calibre.gui2.convert.search_and_replace import SearchAndReplaceWidget
+from calibre.gui2.convert.look_and_feel import LookAndFeelWidget
 from calibre.gui2.convert.page_setup import PageSetupWidget
+from calibre.gui2.convert.search_and_replace import SearchAndReplaceWidget
 from calibre.gui2.convert.structure_detection import StructureDetectionWidget
 from calibre.gui2.convert.toc import TOCWidget
-from calibre.customize.ui import input_format_plugins, output_format_plugins
-from calibre.gui2.convert import config_widget_for_input_plugin
+from calibre.gui2.preferences import AbortCommit, ConfigWidgetBase, test_widget
+from calibre.utils.logging import Log
 
 
 class Model(QStringListModel):
diff --git a/src/calibre/gui2/preferences/create_custom_column.py b/src/calibre/gui2/preferences/create_custom_column.py
index 3e4aaf76c4..3480936c2c 100644
--- a/src/calibre/gui2/preferences/create_custom_column.py
+++ b/src/calibre/gui2/preferences/create_custom_column.py
@@ -10,9 +10,23 @@ import copy
 import re
 from enum import Enum
 from functools import partial
+
 from qt.core import (
-    QCheckBox, QColor, QComboBox, QDialog, QDialogButtonBox, QGridLayout, QGroupBox,
-    QHBoxLayout, QIcon, QLabel, QLineEdit, QRadioButton, QSpinBox, Qt, QVBoxLayout,
+    QCheckBox,
+    QColor,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QRadioButton,
+    QSpinBox,
+    Qt,
+    QVBoxLayout,
     QWidget,
 )
 
diff --git a/src/calibre/gui2/preferences/device_debug.py b/src/calibre/gui2/preferences/device_debug.py
index 3e07b77458..b5494b15bc 100644
--- a/src/calibre/gui2/preferences/device_debug.py
+++ b/src/calibre/gui2/preferences/device_debug.py
@@ -6,8 +6,7 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import QDialog, QVBoxLayout, QPlainTextEdit, QTimer, \
-    QDialogButtonBox, QPushButton, QApplication, QIcon
+from qt.core import QApplication, QDialog, QDialogButtonBox, QIcon, QPlainTextEdit, QPushButton, QTimer, QVBoxLayout
 
 from calibre.gui2 import error_dialog
 
diff --git a/src/calibre/gui2/preferences/device_user_defined.py b/src/calibre/gui2/preferences/device_user_defined.py
index 29529ee556..84f6a7fbe3 100644
--- a/src/calibre/gui2/preferences/device_user_defined.py
+++ b/src/calibre/gui2/preferences/device_user_defined.py
@@ -7,8 +7,8 @@ __docformat__ = 'restructuredtext en'
 
 
 import numbers
-from qt.core import QDialog, QVBoxLayout, QPlainTextEdit, QTimer, \
-    QDialogButtonBox, QPushButton, QApplication, QIcon, QMessageBox
+
+from qt.core import QApplication, QDialog, QDialogButtonBox, QIcon, QMessageBox, QPlainTextEdit, QPushButton, QTimer, QVBoxLayout
 
 
 def step_dialog(parent, title, msg, det_msg=''):
diff --git a/src/calibre/gui2/preferences/emailp.py b/src/calibre/gui2/preferences/emailp.py
index 3b4c34b0a7..2ae7ca1530 100644
--- a/src/calibre/gui2/preferences/emailp.py
+++ b/src/calibre/gui2/preferences/emailp.py
@@ -4,6 +4,7 @@
 
 import re
 import textwrap
+
 from qt.core import QAbstractItemView, QAbstractTableModel, QFont, Qt
 
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/preferences/ignored_devices.py b/src/calibre/gui2/preferences/ignored_devices.py
index aea7328319..1cc65acbbe 100644
--- a/src/calibre/gui2/preferences/ignored_devices.py
+++ b/src/calibre/gui2/preferences/ignored_devices.py
@@ -4,9 +4,7 @@
 
 import textwrap
 
-from qt.core import (
-    QIcon, QLabel, QListWidget, QListWidgetItem, QPushButton, Qt, QVBoxLayout
-)
+from qt.core import QIcon, QLabel, QListWidget, QListWidgetItem, QPushButton, Qt, QVBoxLayout
 
 from calibre.customize.ui import enable_plugin
 from calibre.gui2 import gprefs
diff --git a/src/calibre/gui2/preferences/keyboard.py b/src/calibre/gui2/preferences/keyboard.py
index 061d70d456..44b5fcd258 100644
--- a/src/calibre/gui2/preferences/keyboard.py
+++ b/src/calibre/gui2/preferences/keyboard.py
@@ -7,8 +7,8 @@ __docformat__ = 'restructuredtext en'
 
 from qt.core import QVBoxLayout
 
-from calibre.gui2.preferences import (ConfigWidgetBase, test_widget)
 from calibre.gui2.keyboard import ShortcutConfig
+from calibre.gui2.preferences import ConfigWidgetBase, test_widget
 
 
 class ConfigWidget(ConfigWidgetBase):
diff --git a/src/calibre/gui2/preferences/look_feel.py b/src/calibre/gui2/preferences/look_feel.py
index 9fbf058d62..f4779d6125 100644
--- a/src/calibre/gui2/preferences/look_feel.py
+++ b/src/calibre/gui2/preferences/look_feel.py
@@ -8,23 +8,57 @@ __docformat__ = 'restructuredtext en'
 import json
 from collections import defaultdict
 from functools import partial
-from qt.core import (
-    QAbstractListModel, QApplication, QBrush, QColor, QColorDialog, QComboBox, QDialog,
-    QDialogButtonBox, QFont, QFontDialog, QFontInfo, QFormLayout, QHeaderView, QIcon,
-    QItemSelectionModel, QKeySequence, QLabel, QLineEdit, QListWidgetItem, QPainter,
-    QPixmap, QPushButton, QSize, QSizePolicy, Qt, QTableWidget, QTableWidgetItem,
-    QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 
+from qt.core import (
+    QAbstractListModel,
+    QApplication,
+    QBrush,
+    QColor,
+    QColorDialog,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFontDialog,
+    QFontInfo,
+    QFormLayout,
+    QHeaderView,
+    QIcon,
+    QItemSelectionModel,
+    QKeySequence,
+    QLabel,
+    QLineEdit,
+    QListWidgetItem,
+    QPainter,
+    QPixmap,
+    QPushButton,
+    QSize,
+    QSizePolicy,
+    Qt,
+    QTableWidget,
+    QTableWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import human_readable
 from calibre.constants import ismacos, iswindows
 from calibre.db.categories import is_standard_category
 from calibre.ebooks.metadata.book.render import DEFAULT_AUTHOR_LINK
 from calibre.ebooks.metadata.sources.prefs import msprefs
 from calibre.gui2 import (
-    choose_files, choose_save_file, config, default_author_link, error_dialog, gprefs,
-    icon_resource_manager, open_local_file, qt_app, question_dialog,
+    choose_files,
+    choose_save_file,
+    config,
+    default_author_link,
+    error_dialog,
+    gprefs,
+    icon_resource_manager,
+    open_local_file,
+    qt_app,
+    question_dialog,
 )
 from calibre.gui2.actions.show_quickview import get_quickview_action_plugin
 from calibre.gui2.book_details import get_field_list
@@ -32,9 +66,7 @@ from calibre.gui2.custom_column_widgets import get_field_list as em_get_field_li
 from calibre.gui2.dialogs.quickview import get_qv_field_list
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
 from calibre.gui2.library.alternate_views import CM_TO_INCH, auto_height
-from calibre.gui2.preferences import (
-    ConfigWidgetBase, Setting, set_help_tips, test_widget,
-)
+from calibre.gui2.preferences import ConfigWidgetBase, Setting, set_help_tips, test_widget
 from calibre.gui2.preferences.coloring import EditRules
 from calibre.gui2.preferences.look_feel_ui import Ui_Form
 from calibre.gui2.widgets import BusyCursor
@@ -43,7 +75,8 @@ from calibre.startup import connect_lambda
 from calibre.utils.config import prefs
 from calibre.utils.icu import sort_key
 from calibre.utils.localization import available_translations, get_lang, get_language
-from calibre.utils.resources import get_path as P, set_data
+from calibre.utils.resources import get_path as P
+from calibre.utils.resources import set_data
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/gui2/preferences/main.py b/src/calibre/gui2/preferences/main.py
index 0d331ad5f3..8b78916b04 100644
--- a/src/calibre/gui2/preferences/main.py
+++ b/src/calibre/gui2/preferences/main.py
@@ -9,22 +9,38 @@ import re
 import textwrap
 from collections import OrderedDict
 from functools import partial
+
 from qt.core import (
-    QApplication, QDialog, QDialogButtonBox, QFont, QFrame, QHBoxLayout, QIcon,
-    QLabel, QPainter, QPointF, QPushButton, QScrollArea, QSize, QSizePolicy,
-    QStackedWidget, QStatusTipEvent, Qt, QTabWidget, QTextLayout, QToolBar,
-    QVBoxLayout, QWidget, pyqtSignal
+    QApplication,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFrame,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QPainter,
+    QPointF,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QStackedWidget,
+    QStatusTipEvent,
+    Qt,
+    QTabWidget,
+    QTextLayout,
+    QToolBar,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.constants import __appname__, __version__
 from calibre.customize.ui import preferences_plugins
-from calibre.gui2 import (
-    gprefs, show_restart_warning
-)
+from calibre.gui2 import gprefs, show_restart_warning
 from calibre.gui2.dialogs.message_box import Icon
-from calibre.gui2.preferences import (
-    AbortCommit, AbortInitialize, get_plugin, init_gui
-)
+from calibre.gui2.preferences import AbortCommit, AbortInitialize, get_plugin, init_gui
 
 ICON_SIZE = 32
 
diff --git a/src/calibre/gui2/preferences/metadata_sources.py b/src/calibre/gui2/preferences/metadata_sources.py
index cb9bfe4e97..0ed73a71f1 100644
--- a/src/calibre/gui2/preferences/metadata_sources.py
+++ b/src/calibre/gui2/preferences/metadata_sources.py
@@ -6,15 +6,25 @@ __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from operator import attrgetter
+
 from qt.core import (
-    QAbstractListModel, QAbstractTableModel, QCursor, QDialog, QDialogButtonBox, QFrame,
-    QIcon, QLabel, QMenu, QScrollArea, Qt, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractListModel,
+    QAbstractTableModel,
+    QCursor,
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QIcon,
+    QLabel,
+    QMenu,
+    QScrollArea,
+    Qt,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
-from calibre.customize.ui import (
-    all_metadata_plugins, default_disabled_plugins, disable_plugin, enable_plugin,
-    is_disabled,
-)
+from calibre.customize.ui import all_metadata_plugins, default_disabled_plugins, disable_plugin, enable_plugin, is_disabled
 from calibre.ebooks.metadata.sources.prefs import msprefs
 from calibre.gui2 import error_dialog, question_dialog
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget
diff --git a/src/calibre/gui2/preferences/misc.py b/src/calibre/gui2/preferences/misc.py
index 9ddc27bacc..4f8913dae4 100644
--- a/src/calibre/gui2/preferences/misc.py
+++ b/src/calibre/gui2/preferences/misc.py
@@ -7,10 +7,10 @@ __docformat__ = 'restructuredtext en'
 
 import textwrap
 
-from calibre.gui2.preferences import ConfigWidgetBase, test_widget, Setting
-from calibre.gui2.preferences.misc_ui import Ui_Form
-from calibre.gui2 import config, open_local_file, gprefs
 from calibre import get_proxies
+from calibre.gui2 import config, gprefs, open_local_file
+from calibre.gui2.preferences import ConfigWidgetBase, Setting, test_widget
+from calibre.gui2.preferences.misc_ui import Ui_Form
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/gui2/preferences/plugboard.py b/src/calibre/gui2/preferences/plugboard.py
index b8458d5927..123bd86bf1 100644
--- a/src/calibre/gui2/preferences/plugboard.py
+++ b/src/calibre/gui2/preferences/plugboard.py
@@ -8,20 +8,17 @@ __docformat__ = 'restructuredtext en'
 import copy
 from collections import defaultdict
 
-from qt.core import Qt, QComboBox, QListWidgetItem
+from qt.core import QComboBox, QListWidgetItem, Qt
 
-from calibre.customize.ui import is_disabled
+from calibre.customize.ui import device_plugins, disabled_device_plugins, is_disabled, metadata_writers
 from calibre.gui2 import error_dialog, question_dialog, warning_dialog
 from calibre.gui2.device import device_name_for_plugboards
 from calibre.gui2.dialogs.template_line_editor import TemplateLineEditor
+from calibre.gui2.email import plugboard_email_formats, plugboard_email_value
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget
 from calibre.gui2.preferences.plugboard_ui import Ui_Form
-from calibre.customize.ui import metadata_writers, device_plugins, disabled_device_plugins
-from calibre.library.save_to_disk import plugboard_any_format_value, \
-                    plugboard_any_device_value, plugboard_save_to_disk_value, \
-                    find_plugboard
-from calibre.srv.content import plugboard_content_server_value, plugboard_content_server_formats
-from calibre.gui2.email import plugboard_email_value, plugboard_email_formats
+from calibre.library.save_to_disk import find_plugboard, plugboard_any_device_value, plugboard_any_format_value, plugboard_save_to_disk_value
+from calibre.srv.content import plugboard_content_server_formats, plugboard_content_server_value
 from calibre.utils.formatter import validation_formatter
 
 
diff --git a/src/calibre/gui2/preferences/plugins.py b/src/calibre/gui2/preferences/plugins.py
index 3e21f2829d..8719eefbc8 100644
--- a/src/calibre/gui2/preferences/plugins.py
+++ b/src/calibre/gui2/preferences/plugins.py
@@ -5,24 +5,21 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import textwrap, os
+import os
+import textwrap
 from collections import OrderedDict
 
-from qt.core import (Qt, QMenu, QModelIndex, QAbstractItemModel, QIcon,
-        QBrush, QDialog, QItemSelectionModel, QAbstractItemView)
+from qt.core import QAbstractItemModel, QAbstractItemView, QBrush, QDialog, QIcon, QItemSelectionModel, QMenu, QModelIndex, Qt
 
+from calibre.constants import iswindows
+from calibre.customize import PluginInstallationType
+from calibre.customize.ui import NameConflict, add_plugin, disable_plugin, enable_plugin, initialized_plugins, is_disabled, plugin_customization, remove_plugin
+from calibre.gui2 import choose_files, error_dialog, gprefs, info_dialog, question_dialog
+from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget
 from calibre.gui2.preferences.plugins_ui import Ui_Form
-from calibre.customize import PluginInstallationType
-from calibre.customize.ui import (initialized_plugins, is_disabled, enable_plugin,
-                                 disable_plugin, plugin_customization, add_plugin,
-                                 remove_plugin, NameConflict)
-from calibre.gui2 import (error_dialog, info_dialog, choose_files,
-        question_dialog, gprefs)
-from calibre.gui2.dialogs.confirm_delete import confirm
-from calibre.utils.search_query_parser import SearchQueryParser
 from calibre.utils.icu import lower
-from calibre.constants import iswindows
+from calibre.utils.search_query_parser import SearchQueryParser
 from polyglot.builtins import iteritems, itervalues
 
 
@@ -402,8 +399,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         self.update_plugins(not_installed=True)
 
     def update_plugins(self, not_installed=False):
-        from calibre.gui2.dialogs.plugin_updater import (PluginUpdaterDialog,
-                                FILTER_UPDATE_AVAILABLE, FILTER_NOT_INSTALLED)
+        from calibre.gui2.dialogs.plugin_updater import FILTER_NOT_INSTALLED, FILTER_UPDATE_AVAILABLE, PluginUpdaterDialog
         mode = FILTER_NOT_INSTALLED if not_installed else FILTER_UPDATE_AVAILABLE
         d = PluginUpdaterDialog(self.gui, initial_filter=mode)
         d.exec()
@@ -420,8 +416,8 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
             self.gui.iactions['Store'].load_menu()
 
     def check_for_add_to_toolbars(self, plugin, previously_installed=True):
+        from calibre.customize import EditBookToolPlugin, InterfaceActionBase
         from calibre.gui2.preferences.toolbar import ConfigWidget
-        from calibre.customize import InterfaceActionBase, EditBookToolPlugin
 
         if isinstance(plugin, EditBookToolPlugin):
             return self.check_for_add_to_editor_toolbar(plugin, previously_installed)
diff --git a/src/calibre/gui2/preferences/save_template.py b/src/calibre/gui2/preferences/save_template.py
index f3e573e5d3..f9ed14604b 100644
--- a/src/calibre/gui2/preferences/save_template.py
+++ b/src/calibre/gui2/preferences/save_template.py
@@ -8,10 +8,10 @@ __docformat__ = 'restructuredtext en'
 from qt.core import QWidget, pyqtSignal
 
 from calibre.gui2 import error_dialog, question_dialog
+from calibre.gui2.dialogs.template_dialog import TemplateDialog
 from calibre.gui2.preferences.save_template_ui import Ui_Form
 from calibre.library.save_to_disk import FORMAT_ARG_DESCS, preprocess_template
 from calibre.utils.formatter import validation_formatter
-from calibre.gui2.dialogs.template_dialog import TemplateDialog
 
 
 class SaveTemplate(QWidget, Ui_Form):
diff --git a/src/calibre/gui2/preferences/saving.py b/src/calibre/gui2/preferences/saving.py
index 7325dafd68..d2280760c0 100644
--- a/src/calibre/gui2/preferences/saving.py
+++ b/src/calibre/gui2/preferences/saving.py
@@ -6,12 +6,11 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.preferences import ConfigWidgetBase, test_widget, \
-        AbortCommit
-from calibre.gui2.preferences.saving_ui import Ui_Form
-from calibre.utils.config import ConfigProxy
-from calibre.library.save_to_disk import config
 from calibre.gui2 import gprefs
+from calibre.gui2.preferences import AbortCommit, ConfigWidgetBase, test_widget
+from calibre.gui2.preferences.saving_ui import Ui_Form
+from calibre.library.save_to_disk import config
+from calibre.utils.config import ConfigProxy
 
 
 class ConfigWidget(ConfigWidgetBase, Ui_Form):
diff --git a/src/calibre/gui2/preferences/search.py b/src/calibre/gui2/preferences/search.py
index 961c7cc1a6..6ec50332c5 100644
--- a/src/calibre/gui2/preferences/search.py
+++ b/src/calibre/gui2/preferences/search.py
@@ -8,13 +8,12 @@ __docformat__ = 'restructuredtext en'
 from qt.core import QApplication, QTimer
 
 from calibre.gui2 import config, error_dialog, gprefs
-from calibre.gui2.preferences import (
-    AbortCommit, CommaSeparatedList, ConfigWidgetBase, test_widget,
-)
+from calibre.gui2.preferences import AbortCommit, CommaSeparatedList, ConfigWidgetBase, test_widget
 from calibre.gui2.preferences.search_ui import Ui_Form
 from calibre.library.caches import set_use_primary_find_in_search
 from calibre.utils.config import prefs
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/gui2/preferences/sending.py b/src/calibre/gui2/preferences/sending.py
index 93e108cf7d..14df6ce7b2 100644
--- a/src/calibre/gui2/preferences/sending.py
+++ b/src/calibre/gui2/preferences/sending.py
@@ -6,12 +6,10 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-from calibre.gui2.preferences import ConfigWidgetBase, test_widget, \
-        AbortCommit
+from calibre.gui2.preferences import AbortCommit, ConfigWidgetBase, test_widget
 from calibre.gui2.preferences.sending_ui import Ui_Form
-from calibre.utils.config import ConfigProxy
 from calibre.library.save_to_disk import config
-from calibre.utils.config import prefs
+from calibre.utils.config import ConfigProxy, prefs
 
 
 class ConfigWidget(ConfigWidgetBase, Ui_Form):
diff --git a/src/calibre/gui2/preferences/server.py b/src/calibre/gui2/preferences/server.py
index 33f1e87489..2aeaeac5c5 100644
--- a/src/calibre/gui2/preferences/server.py
+++ b/src/calibre/gui2/preferences/server.py
@@ -8,19 +8,42 @@ import os
 import sys
 import textwrap
 import time
+
 from qt.core import (
-    QApplication, QCheckBox, QComboBox, QDialog, QDialogButtonBox, QDoubleSpinBox,
-    QFormLayout, QFrame, QHBoxLayout, QIcon, QLabel, QLayout, QLineEdit, QListWidget,
-    QPlainTextEdit, QPushButton, QScrollArea, QSize, QSizePolicy, QSpinBox, Qt,
-    QTabWidget, QTimer, QToolButton, QUrl, QVBoxLayout, QWidget, pyqtSignal, sip,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QDoubleSpinBox,
+    QFormLayout,
+    QFrame,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLayout,
+    QLineEdit,
+    QListWidget,
+    QPlainTextEdit,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QSpinBox,
+    Qt,
+    QTabWidget,
+    QTimer,
+    QToolButton,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+    sip,
 )
 
 from calibre import as_unicode
 from calibre.constants import isportable, iswindows
-from calibre.gui2 import (
-    choose_files, choose_save_file, config, error_dialog, gprefs, info_dialog, open_url,
-    warning_dialog,
-)
+from calibre.gui2 import choose_files, choose_save_file, config, error_dialog, gprefs, info_dialog, open_url, warning_dialog
 from calibre.gui2.preferences import AbortCommit, ConfigWidgetBase, test_widget
 from calibre.gui2.widgets import HistoryLineEdit
 from calibre.srv.code import custom_list_template as default_custom_list_template
@@ -28,9 +51,7 @@ from calibre.srv.embedded import custom_list_template, search_the_net_urls
 from calibre.srv.library_broker import load_gui_libraries
 from calibre.srv.loop import parse_trusted_ips
 from calibre.srv.opts import change_settings, options, server_config
-from calibre.srv.users import (
-    UserManager, create_user_data, validate_password, validate_username,
-)
+from calibre.srv.users import UserManager, create_user_data, validate_password, validate_username
 from calibre.utils.icu import primary_sort_key
 from calibre.utils.localization import ngettext
 from calibre.utils.shared_file import share_open
diff --git a/src/calibre/gui2/preferences/template_functions.py b/src/calibre/gui2/preferences/template_functions.py
index 097e4f4621..68fab7cb73 100644
--- a/src/calibre/gui2/preferences/template_functions.py
+++ b/src/calibre/gui2/preferences/template_functions.py
@@ -4,6 +4,7 @@
 import copy
 import json
 import traceback
+
 from qt.core import QDialog, QDialogButtonBox
 
 from calibre.gui2 import error_dialog, gprefs, question_dialog, warning_dialog
@@ -12,8 +13,12 @@ from calibre.gui2.preferences import AbortInitialize, ConfigWidgetBase, test_wid
 from calibre.gui2.preferences.template_functions_ui import Ui_Form
 from calibre.gui2.widgets import PythonHighlighter
 from calibre.utils.formatter_functions import (
-    StoredObjectType, compile_user_function, compile_user_template_functions,
-    formatter_functions, function_object_type, function_pref_name,
+    StoredObjectType,
+    compile_user_function,
+    compile_user_template_functions,
+    formatter_functions,
+    function_object_type,
+    function_pref_name,
     load_user_template_functions,
 )
 from calibre.utils.resources import get_path as P
diff --git a/src/calibre/gui2/preferences/texture_chooser.py b/src/calibre/gui2/preferences/texture_chooser.py
index 08ac8ab07d..b3659c05ee 100644
--- a/src/calibre/gui2/preferences/texture_chooser.py
+++ b/src/calibre/gui2/preferences/texture_chooser.py
@@ -8,9 +8,21 @@ import glob
 import os
 import shutil
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QApplication, QDialog, QDialogButtonBox, QIcon, QLabel,
-    QListView, QListWidget, QListWidgetItem, QSize, Qt, QTimer, QVBoxLayout,
+    QAbstractItemView,
+    QApplication,
+    QDialog,
+    QDialogButtonBox,
+    QIcon,
+    QLabel,
+    QListView,
+    QListWidget,
+    QListWidgetItem,
+    QSize,
+    Qt,
+    QTimer,
+    QVBoxLayout,
 )
 
 from calibre.constants import config_dir
diff --git a/src/calibre/gui2/preferences/tweaks.py b/src/calibre/gui2/preferences/tweaks.py
index f260400c8d..a0f1e17a70 100644
--- a/src/calibre/gui2/preferences/tweaks.py
+++ b/src/calibre/gui2/preferences/tweaks.py
@@ -7,23 +7,41 @@ from collections import OrderedDict
 from functools import partial
 from operator import attrgetter
 
+from qt.core import (
+    QAbstractItemView,
+    QAbstractListModel,
+    QApplication,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QGridLayout,
+    QGroupBox,
+    QIcon,
+    QItemSelectionModel,
+    QLabel,
+    QListView,
+    QMenu,
+    QModelIndex,
+    QPlainTextEdit,
+    QPushButton,
+    QSizePolicy,
+    QSplitter,
+    Qt,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import isbytestring, prepare_string_for_xml
 from calibre.gui2 import error_dialog, info_dialog
 from calibre.gui2.preferences import AbortCommit, ConfigWidgetBase, test_widget
 from calibre.gui2.search_box import SearchBox2
 from calibre.gui2.widgets import PythonHighlighter
-from calibre.utils.config_base import (default_tweaks_raw, exec_tweaks,
-                                       normalize_tweak, read_custom_tweaks,
-                                       write_custom_tweaks)
+from calibre.utils.config_base import default_tweaks_raw, exec_tweaks, normalize_tweak, read_custom_tweaks, write_custom_tweaks
 from calibre.utils.icu import lower
 from calibre.utils.search_query_parser import ParseException, SearchQueryParser
 from polyglot.builtins import iteritems
-from qt.core import (QAbstractItemView, QAbstractListModel, QApplication,
-                     QComboBox, QDialog, QDialogButtonBox, QFont, QGridLayout,
-                     QGroupBox, QIcon, QItemSelectionModel, QLabel, QListView,
-                     QMenu, QModelIndex, QPlainTextEdit, QPushButton,
-                     QSizePolicy, Qt, QVBoxLayout, QWidget, QSplitter,
-                     pyqtSignal)
 
 ROOT = QModelIndex()
 
diff --git a/src/calibre/gui2/proceed.py b/src/calibre/gui2/proceed.py
index 96beb32f39..532df23744 100644
--- a/src/calibre/gui2/proceed.py
+++ b/src/calibre/gui2/proceed.py
@@ -6,11 +6,34 @@ __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from collections import namedtuple
+
 from qt.core import (
-    QApplication, QCheckBox, QDialogButtonBox, QEasingCurve, QEvent, QFontMetrics,
-    QHBoxLayout, QIcon, QImage, QLabel, QPainter, QPainterPath, QPalette, QPixmap,
-    QPlainTextEdit, QPropertyAnimation, QRectF, QSize, QSizePolicy, Qt, QTimer,
-    QVBoxLayout, QWidget, pyqtProperty, pyqtSignal, sip,
+    QApplication,
+    QCheckBox,
+    QDialogButtonBox,
+    QEasingCurve,
+    QEvent,
+    QFontMetrics,
+    QHBoxLayout,
+    QIcon,
+    QImage,
+    QLabel,
+    QPainter,
+    QPainterPath,
+    QPalette,
+    QPixmap,
+    QPlainTextEdit,
+    QPropertyAnimation,
+    QRectF,
+    QSize,
+    QSizePolicy,
+    Qt,
+    QTimer,
+    QVBoxLayout,
+    QWidget,
+    pyqtProperty,
+    pyqtSignal,
+    sip,
 )
 
 from calibre.constants import __version__
diff --git a/src/calibre/gui2/progress_indicator/__init__.py b/src/calibre/gui2/progress_indicator/__init__.py
index 052be0695a..24c797bec2 100644
--- a/src/calibre/gui2/progress_indicator/__init__.py
+++ b/src/calibre/gui2/progress_indicator/__init__.py
@@ -1,14 +1,10 @@
 #!/usr/bin/env python
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
-from qt.core import (
-    QDialog, QLabel, QObject, QSizePolicy, QStackedLayout, QStackedWidget, Qt,
-    QVBoxLayout, QWidget, pyqtSignal
-)
+from qt.core import QDialog, QLabel, QObject, QSizePolicy, QStackedLayout, QStackedWidget, Qt, QVBoxLayout, QWidget, pyqtSignal
 
-from calibre_extensions.progress_indicator import (
-    QProgressIndicator as ProgressIndicator, draw_snake_spinner
-)
+from calibre_extensions.progress_indicator import QProgressIndicator as ProgressIndicator
+from calibre_extensions.progress_indicator import draw_snake_spinner
 
 draw_snake_spinner
 
diff --git a/src/calibre/gui2/publisher_mapper.py b/src/calibre/gui2/publisher_mapper.py
index f57c1f58fb..bb4a5bc1da 100644
--- a/src/calibre/gui2/publisher_mapper.py
+++ b/src/calibre/gui2/publisher_mapper.py
@@ -6,11 +6,12 @@ from collections import OrderedDict
 
 from calibre.ebooks.metadata.tag_mapper import map_tags
 from calibre.gui2 import Application, elided_text
-from calibre.gui2.tag_mapper import (
-    RuleEdit as RuleEditBase, RuleEditDialog as RuleEditDialogBase,
-    RuleItem as RuleItemBase, Rules as RulesBase, RulesDialog as RulesDialogBase,
-    Tester as TesterBase,
-)
+from calibre.gui2.tag_mapper import RuleEdit as RuleEditBase
+from calibre.gui2.tag_mapper import RuleEditDialog as RuleEditDialogBase
+from calibre.gui2.tag_mapper import RuleItem as RuleItemBase
+from calibre.gui2.tag_mapper import Rules as RulesBase
+from calibre.gui2.tag_mapper import RulesDialog as RulesDialogBase
+from calibre.gui2.tag_mapper import Tester as TesterBase
 from calibre.utils.config import JSONConfig
 
 publisher_maps = JSONConfig('publisher-mapping-rules')
diff --git a/src/calibre/gui2/pyqt6_compat.py b/src/calibre/gui2/pyqt6_compat.py
index c90507efcc..05fa05018f 100644
--- a/src/calibre/gui2/pyqt6_compat.py
+++ b/src/calibre/gui2/pyqt6_compat.py
@@ -6,11 +6,33 @@
 # party plugin code, we NEED backward compat.
 
 from qt.core import (
-    QAbstractItemView, QAction, QComboBox, QCoreApplication, QDialog,
-    QDialogButtonBox, QDrag, QDropEvent, QEvent, QEventLoop, QFontMetrics,
-    QFormLayout, QFrame, QHoverEvent, QImage, QIODevice, QLayout, QLineEdit, QMenu,
-    QMessageBox, QModelIndex, QPalette, QSinglePointEvent, QSizePolicy, Qt, QThread,
-    QToolButton
+    QAbstractItemView,
+    QAction,
+    QComboBox,
+    QCoreApplication,
+    QDialog,
+    QDialogButtonBox,
+    QDrag,
+    QDropEvent,
+    QEvent,
+    QEventLoop,
+    QFontMetrics,
+    QFormLayout,
+    QFrame,
+    QHoverEvent,
+    QImage,
+    QIODevice,
+    QLayout,
+    QLineEdit,
+    QMenu,
+    QMessageBox,
+    QModelIndex,
+    QPalette,
+    QSinglePointEvent,
+    QSizePolicy,
+    Qt,
+    QThread,
+    QToolButton,
 )
 
 from calibre_extensions import progress_indicator
diff --git a/src/calibre/gui2/qt_file_dialogs.py b/src/calibre/gui2/qt_file_dialogs.py
index b7c387c1b3..da27487567 100644
--- a/src/calibre/gui2/qt_file_dialogs.py
+++ b/src/calibre/gui2/qt_file_dialogs.py
@@ -4,7 +4,7 @@
 
 import os
 
-from qt.core import QFileDialog, QObject, QDialog
+from qt.core import QDialog, QFileDialog, QObject
 
 from calibre.gui2.linux_file_dialogs import dialog_name, image_extensions
 from polyglot.builtins import string_or_bytes
diff --git a/src/calibre/gui2/save.py b/src/calibre/gui2/save.py
index 6be6703b0e..b21dde9b93 100644
--- a/src/calibre/gui2/save.py
+++ b/src/calibre/gui2/save.py
@@ -10,20 +10,19 @@ import shutil
 import time
 import traceback
 from collections import defaultdict, namedtuple
+
 from qt.core import QObject, Qt, pyqtSignal
 
 from calibre import force_unicode, prints
 from calibre.constants import DEBUG
 from calibre.customize.ui import can_set_metadata
-from calibre.db.errors import NoSuchFormat
 from calibre.db.constants import DATA_FILE_PATTERN
+from calibre.db.errors import NoSuchFormat
 from calibre.ebooks.metadata import authors_to_string
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
 from calibre.gui2 import error_dialog, gprefs, open_local_file, warning_dialog
 from calibre.gui2.dialogs.progress import ProgressDialog
-from calibre.library.save_to_disk import (
-    find_plugboard, get_path_components, plugboard_save_to_disk_value, sanitize_args,
-)
+from calibre.library.save_to_disk import find_plugboard, get_path_components, plugboard_save_to_disk_value, sanitize_args
 from calibre.ptempfile import PersistentTemporaryDirectory, SpooledTemporaryFile
 from calibre.utils.filenames import make_long_path_useable
 from calibre.utils.ipc.pool import Failure, Pool
diff --git a/src/calibre/gui2/search_box.py b/src/calibre/gui2/search_box.py
index d676b7c35b..92953f3067 100644
--- a/src/calibre/gui2/search_box.py
+++ b/src/calibre/gui2/search_box.py
@@ -8,10 +8,8 @@ __docformat__ = 'restructuredtext en'
 import re
 import time
 from functools import partial
-from qt.core import (
-    QAction, QApplication, QComboBox, QCompleter, QDialog, QEvent, QIcon, QKeyEvent,
-    QKeySequence, QLineEdit, Qt, QTimer, pyqtSignal, pyqtSlot,
-)
+
+from qt.core import QAction, QApplication, QComboBox, QCompleter, QDialog, QEvent, QIcon, QKeyEvent, QKeySequence, QLineEdit, Qt, QTimer, pyqtSignal, pyqtSlot
 
 from calibre.gui2 import QT_HIDDEN_CLEAR_ACTION, config, gprefs, question_dialog
 from calibre.gui2.dialogs.saved_search_editor import SavedSearchEditor
diff --git a/src/calibre/gui2/search_restriction_mixin.py b/src/calibre/gui2/search_restriction_mixin.py
index f6912d7576..3fdcef8812 100644
--- a/src/calibre/gui2/search_restriction_mixin.py
+++ b/src/calibre/gui2/search_restriction_mixin.py
@@ -5,10 +5,27 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QAction, QComboBox, QDialog, QDialogButtonBox, QFrame,
-    QGridLayout, QIcon, QLabel, QLineEdit, QListView, QMenu, QRadioButton, QSize,
-    QSortFilterProxyModel, QStringListModel, Qt, QTextBrowser, QVBoxLayout,
+    QAbstractItemView,
+    QAction,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QGridLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QMenu,
+    QRadioButton,
+    QSize,
+    QSortFilterProxyModel,
+    QStringListModel,
+    Qt,
+    QTextBrowser,
+    QVBoxLayout,
 )
 
 from calibre.gui2 import error_dialog, gprefs, question_dialog
diff --git a/src/calibre/gui2/splash_screen.py b/src/calibre/gui2/splash_screen.py
index 165f25873b..b7600e32fa 100644
--- a/src/calibre/gui2/splash_screen.py
+++ b/src/calibre/gui2/splash_screen.py
@@ -2,10 +2,7 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QApplication, QBrush, QColor, QFont, QFontMetrics, QPainter, QPen, QPixmap,
-    QSplashScreen, Qt,
-)
+from qt.core import QApplication, QBrush, QColor, QFont, QFontMetrics, QPainter, QPen, QPixmap, QSplashScreen, Qt
 
 from calibre.constants import __appname__, numeric_version
 from calibre.utils.monotonic import monotonic
diff --git a/src/calibre/gui2/store/amazon_base.py b/src/calibre/gui2/store/amazon_base.py
index 825b0314c1..9275813382 100644
--- a/src/calibre/gui2/store/amazon_base.py
+++ b/src/calibre/gui2/store/amazon_base.py
@@ -1,12 +1,12 @@
 #!/usr/bin/env python
 # License: GPL v3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
 
-from qt.core import QUrl
 from threading import Lock
 from time import monotonic
 
-from calibre.gui2 import open_url
+from qt.core import QUrl
 
+from calibre.gui2 import open_url
 
 lock = Lock()
 cached_mod = None
@@ -20,7 +20,7 @@ def live_module():
         if now - cached_time > 3600:
             cached_mod = None
         if cached_mod is None:
-            from calibre.live import load_module, Strategy
+            from calibre.live import Strategy, load_module
             cached_mod = load_module('calibre.gui2.store.amazon_live', strategy=Strategy.fast)
         return cached_mod
 
diff --git a/src/calibre/gui2/store/amazon_live.py b/src/calibre/gui2/store/amazon_live.py
index 6a778c2bee..4aaba032bc 100644
--- a/src/calibre/gui2/store/amazon_live.py
+++ b/src/calibre/gui2/store/amazon_live.py
@@ -2,12 +2,12 @@
 # License: GPL v3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from lxml import etree, html
 from urllib.parse import urlencode
 
-from calibre.scraper.simple import read_url
-from calibre.gui2.store.search_result import SearchResult
+from lxml import etree, html
 
+from calibre.gui2.store.search_result import SearchResult
+from calibre.scraper.simple import read_url
 
 module_version = 1  # needed for live updates
 
diff --git a/src/calibre/gui2/store/config/chooser/adv_search_builder.py b/src/calibre/gui2/store/config/chooser/adv_search_builder.py
index 716c1c88f6..ca6129fddf 100644
--- a/src/calibre/gui2/store/config/chooser/adv_search_builder.py
+++ b/src/calibre/gui2/store/config/chooser/adv_search_builder.py
@@ -4,7 +4,7 @@ __docformat__ = 'restructuredtext en'
 
 import re
 
-from qt.core import (QDialog, QDialogButtonBox)
+from qt.core import QDialog, QDialogButtonBox
 
 from calibre.gui2.store.config.chooser.adv_search_builder_ui import Ui_Dialog
 from calibre.library.caches import CONTAINS_MATCH, EQUALS_MATCH
diff --git a/src/calibre/gui2/store/config/chooser/chooser_dialog.py b/src/calibre/gui2/store/config/chooser/chooser_dialog.py
index d1550251f9..2d379d620a 100644
--- a/src/calibre/gui2/store/config/chooser/chooser_dialog.py
+++ b/src/calibre/gui2/store/config/chooser/chooser_dialog.py
@@ -2,7 +2,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import (QDialog, QDialogButtonBox, QVBoxLayout)
+from qt.core import QDialog, QDialogButtonBox, QVBoxLayout
 
 from calibre.gui2.store.config.chooser.chooser_widget import StoreChooserWidget
 
diff --git a/src/calibre/gui2/store/config/chooser/chooser_widget.py b/src/calibre/gui2/store/config/chooser/chooser_widget.py
index 275c8808f3..b611b24138 100644
--- a/src/calibre/gui2/store/config/chooser/chooser_widget.py
+++ b/src/calibre/gui2/store/config/chooser/chooser_widget.py
@@ -2,7 +2,7 @@ __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
-from qt.core import QWidget, QIcon, QDialog, QComboBox, QLineEdit
+from qt.core import QComboBox, QDialog, QIcon, QLineEdit, QWidget
 
 from calibre.gui2.store.config.chooser.adv_search_builder import AdvSearchBuilderDialog
 from calibre.gui2.store.config.chooser.chooser_widget_ui import Ui_Form
diff --git a/src/calibre/gui2/store/config/chooser/models.py b/src/calibre/gui2/store/config/chooser/models.py
index 8cf971d327..cb2270109d 100644
--- a/src/calibre/gui2/store/config/chooser/models.py
+++ b/src/calibre/gui2/store/config/chooser/models.py
@@ -3,9 +3,7 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import (
-    QAbstractItemModel, QIcon, QModelIndex, QStyledItemDelegate, Qt
-)
+from qt.core import QAbstractItemModel, QIcon, QModelIndex, QStyledItemDelegate, Qt
 
 from calibre import fit_image
 from calibre.customize.ui import disable_plugin, enable_plugin, is_disabled
diff --git a/src/calibre/gui2/store/config/chooser/results_view.py b/src/calibre/gui2/store/config/chooser/results_view.py
index 3eafc6cdd2..50604f5c1f 100644
--- a/src/calibre/gui2/store/config/chooser/results_view.py
+++ b/src/calibre/gui2/store/config/chooser/results_view.py
@@ -4,11 +4,11 @@ __docformat__ = 'restructuredtext en'
 
 from functools import partial
 
-from qt.core import (Qt, QTreeView, QSize, QMenu)
+from qt.core import QMenu, QSize, Qt, QTreeView
 
 from calibre.customize.ui import store_plugins
 from calibre.gui2.metadata.single_download import RichTextDelegate
-from calibre.gui2.store.config.chooser.models import Matches, Delegate
+from calibre.gui2.store.config.chooser.models import Delegate, Matches
 
 
 class ResultsView(QTreeView):
diff --git a/src/calibre/gui2/store/loader.py b/src/calibre/gui2/store/loader.py
index 19595bde51..cd792ca88c 100644
--- a/src/calibre/gui2/store/loader.py
+++ b/src/calibre/gui2/store/loader.py
@@ -5,17 +5,20 @@ __license__   = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, time, io, re
-from zlib import decompressobj
+import io
+import re
+import sys
+import time
 from collections import OrderedDict
 from threading import Thread
+from zlib import decompressobj
 
 from calibre import prints
-from calibre.constants import numeric_version, DEBUG
+from calibre.constants import DEBUG, numeric_version
 from calibre.gui2.store import StorePlugin
 from calibre.utils.config import JSONConfig
-from polyglot.urllib import urlencode
 from polyglot.builtins import iteritems, itervalues
+from polyglot.urllib import urlencode
 
 
 class VersionMismatch(ValueError):
diff --git a/src/calibre/gui2/store/opensearch_store.py b/src/calibre/gui2/store/opensearch_store.py
index 110ed81e0b..f7c6577e6f 100644
--- a/src/calibre/gui2/store/opensearch_store.py
+++ b/src/calibre/gui2/store/opensearch_store.py
@@ -6,14 +6,14 @@ from contextlib import closing
 
 from qt.core import QUrl
 
-from calibre import (browser, guess_extension)
+from calibre import browser, guess_extension
 from calibre.gui2 import open_url
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.gui2.store import StorePlugin
 from calibre.gui2.store.search_result import SearchResult
 from calibre.gui2.store.web_store_dialog import WebStoreDialog
 from calibre.utils.opensearch.description import Description
 from calibre.utils.opensearch.query import Query
+from calibre.utils.xml_parse import safe_xml_fromstring
 
 
 def open_search(url, query, max_results=10, timeout=60):
diff --git a/src/calibre/gui2/store/search/adv_search_builder.py b/src/calibre/gui2/store/search/adv_search_builder.py
index a0b6c08ead..c6442c89ec 100644
--- a/src/calibre/gui2/store/search/adv_search_builder.py
+++ b/src/calibre/gui2/store/search/adv_search_builder.py
@@ -4,7 +4,7 @@ __docformat__ = 'restructuredtext en'
 
 import re
 
-from qt.core import (QDialog, QDialogButtonBox)
+from qt.core import QDialog, QDialogButtonBox
 
 from calibre.gui2.store.search.adv_search_builder_ui import Ui_Dialog
 from calibre.library.caches import CONTAINS_MATCH, EQUALS_MATCH
diff --git a/src/calibre/gui2/store/search/download_thread.py b/src/calibre/gui2/store/search/download_thread.py
index dbe3dcdf72..d34d889459 100644
--- a/src/calibre/gui2/store/search/download_thread.py
+++ b/src/calibre/gui2/store/search/download_thread.py
@@ -9,8 +9,8 @@ from threading import Thread
 from calibre import browser
 from calibre.constants import DEBUG
 from calibre.utils.img import scale_image
-from polyglot.queue import Queue
 from polyglot.binary import from_base64_bytes
+from polyglot.queue import Queue
 
 
 class GenericDownloadThreadPool:
diff --git a/src/calibre/gui2/store/search/models.py b/src/calibre/gui2/store/search/models.py
index 5dffa9a283..9cbdbf9e5d 100644
--- a/src/calibre/gui2/store/search/models.py
+++ b/src/calibre/gui2/store/search/models.py
@@ -5,16 +5,15 @@ __docformat__ = 'restructuredtext en'
 import re
 import string
 from operator import attrgetter
-from qt.core import (
-    QAbstractItemModel, QApplication, QIcon, QModelIndex, QPixmap, QSize, Qt,
-    pyqtSignal,
-)
+
+from qt.core import QAbstractItemModel, QApplication, QIcon, QModelIndex, QPixmap, QSize, Qt, pyqtSignal
 
 from calibre import force_unicode
 from calibre.gui2 import FunctionDispatcher
 from calibre.gui2.store.search.download_thread import CoverThreadPool, DetailsThreadPool
 from calibre.gui2.store.search_result import SearchResult
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 from calibre.utils.localization import pgettext
 from calibre.utils.search_query_parser import SearchQueryParser
 
diff --git a/src/calibre/gui2/store/search/results_view.py b/src/calibre/gui2/store/search/results_view.py
index b449521e60..cb3c5f163f 100644
--- a/src/calibre/gui2/store/search/results_view.py
+++ b/src/calibre/gui2/store/search/results_view.py
@@ -4,8 +4,7 @@ __docformat__ = 'restructuredtext en'
 
 from functools import partial
 
-from qt.core import (
-    pyqtSignal, QMenu, QTreeView, QStyledItemDelegate, Qt, QIcon)
+from qt.core import QIcon, QMenu, QStyledItemDelegate, Qt, QTreeView, pyqtSignal
 
 from calibre import fit_image
 from calibre.gui2 import empty_index
diff --git a/src/calibre/gui2/store/search/search.py b/src/calibre/gui2/store/search/search.py
index f2f9a3aa84..9b870884ca 100644
--- a/src/calibre/gui2/store/search/search.py
+++ b/src/calibre/gui2/store/search/search.py
@@ -5,18 +5,16 @@ __docformat__ = 'restructuredtext en'
 import re
 from random import shuffle
 
-from qt.core import (Qt, QDialog, QDialogButtonBox, QTimer, QCheckBox, QLabel,
-                      QVBoxLayout, QIcon, QWidget, QTabWidget, QGridLayout, QSize, QStyle)
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QSize, QStyle, Qt, QTabWidget, QTimer, QVBoxLayout, QWidget
 
-from calibre.gui2 import JSONConfig, info_dialog, error_dialog
+from calibre.gui2 import JSONConfig, error_dialog, info_dialog
 from calibre.gui2.dialogs.choose_format import ChooseFormatDialog
 from calibre.gui2.ebook_download import show_download_info
 from calibre.gui2.progress_indicator import ProgressIndicator
 from calibre.gui2.store.config.chooser.chooser_widget import StoreChooserWidget
 from calibre.gui2.store.config.search.search_widget import StoreConfigWidget
 from calibre.gui2.store.search.adv_search_builder import AdvSearchBuilderDialog
-from calibre.gui2.store.search.download_thread import SearchThreadPool, \
-    CacheUpdateThreadPool
+from calibre.gui2.store.search.download_thread import CacheUpdateThreadPool, SearchThreadPool
 from calibre.gui2.store.search.search_ui import Ui_Dialog
 from calibre.utils.filenames import ascii_filename
 
@@ -451,9 +449,10 @@ class SearchDialog(QDialog, Ui_Dialog):
 
 
 if __name__ == '__main__':
+    import sys
+
     from calibre.gui2 import Application
     from calibre.gui2.preferences.main import init_gui
-    import sys
     app = Application([])
     app
     gui = init_gui()
diff --git a/src/calibre/gui2/store/stores/amazon_au_plugin.py b/src/calibre/gui2/store/stores/amazon_au_plugin.py
index 347e6e5fd3..4833411558 100644
--- a/src/calibre/gui2/store/stores/amazon_au_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_au_plugin.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 20  # Needed for dynamic plugin loading
 
 from calibre.gui2.store import StorePlugin
+
 try:
     from calibre.gui2.store.amazon_base import AmazonStore
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/amazon_ca_plugin.py b/src/calibre/gui2/store/stores/amazon_ca_plugin.py
index 1bacb9342c..31770ea66a 100644
--- a/src/calibre/gui2/store/stores/amazon_ca_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_ca_plugin.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 20  # Needed for dynamic plugin loading
 
 from calibre.gui2.store import StorePlugin
+
 try:
     from calibre.gui2.store.amazon_base import AmazonStore
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/amazon_de_plugin.py b/src/calibre/gui2/store/stores/amazon_de_plugin.py
index 491f2538fb..17c64fae3a 100644
--- a/src/calibre/gui2/store/stores/amazon_de_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_de_plugin.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 16  # Needed for dynamic plugin loading
 
 from calibre.gui2.store import StorePlugin
+
 try:
     from calibre.gui2.store.amazon_base import AmazonStore
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/amazon_es_plugin.py b/src/calibre/gui2/store/stores/amazon_es_plugin.py
index d9fca8e33c..64a2620d07 100644
--- a/src/calibre/gui2/store/stores/amazon_es_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_es_plugin.py
@@ -6,13 +6,13 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 15  # Needed for dynamic plugin loading
 
 from contextlib import closing
+
 try:
     from urllib.parse import urlencode
 except ImportError:
     from urllib import urlencode
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/amazon_fr_plugin.py b/src/calibre/gui2/store/stores/amazon_fr_plugin.py
index f61624fbd9..b198da66be 100644
--- a/src/calibre/gui2/store/stores/amazon_fr_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_fr_plugin.py
@@ -6,13 +6,13 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 16  # Needed for dynamic plugin loading
 
 from contextlib import closing
+
 try:
     from urllib.parse import urlencode
 except ImportError:
     from urllib import urlencode
 
-from lxml import html, etree
-
+from lxml import etree, html
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/amazon_in_plugin.py b/src/calibre/gui2/store/stores/amazon_in_plugin.py
index 18fcd72c59..46894cdb1a 100644
--- a/src/calibre/gui2/store/stores/amazon_in_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_in_plugin.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 20  # Needed for dynamic plugin loading
 
 from calibre.gui2.store import StorePlugin
+
 try:
     from calibre.gui2.store.amazon_base import AmazonStore
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/amazon_it_plugin.py b/src/calibre/gui2/store/stores/amazon_it_plugin.py
index 58c72083fa..c7c2617729 100644
--- a/src/calibre/gui2/store/stores/amazon_it_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_it_plugin.py
@@ -6,13 +6,13 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 15  # Needed for dynamic plugin loading
 
 from contextlib import closing
+
 try:
     from urllib.parse import urlencode
 except ImportError:
     from urllib import urlencode
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/amazon_mx_plugin.py b/src/calibre/gui2/store/stores/amazon_mx_plugin.py
index c648384600..1a334cec97 100644
--- a/src/calibre/gui2/store/stores/amazon_mx_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_mx_plugin.py
@@ -5,6 +5,7 @@
 store_version = 1  # Needed for dynamic plugin loading
 
 from calibre.gui2.store import StorePlugin
+
 try:
     from calibre.gui2.store.amazon_base import AmazonStore
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/amazon_plugin.py b/src/calibre/gui2/store/stores/amazon_plugin.py
index 605efb3b44..9b2c2aa477 100644
--- a/src/calibre/gui2/store/stores/amazon_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_plugin.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 20  # Needed for dynamic plugin loading
 
 from calibre.gui2.store import StorePlugin
+
 try:
     from calibre.gui2.store.amazon_base import AmazonStore
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/amazon_uk_plugin.py b/src/calibre/gui2/store/stores/amazon_uk_plugin.py
index 76a9615902..8a9c462134 100644
--- a/src/calibre/gui2/store/stores/amazon_uk_plugin.py
+++ b/src/calibre/gui2/store/stores/amazon_uk_plugin.py
@@ -6,6 +6,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 20  # Needed for dynamic plugin loading
 
 from calibre.gui2.store import StorePlugin
+
 try:
     from calibre.gui2.store.amazon_base import AmazonStore
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/baen_webscription_plugin.py b/src/calibre/gui2/store/stores/baen_webscription_plugin.py
index d56b7243e9..b13d9ba674 100644
--- a/src/calibre/gui2/store/stores/baen_webscription_plugin.py
+++ b/src/calibre/gui2/store/stores/baen_webscription_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import urlencode
 except ImportError:
     from urllib import urlencode
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py b/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py
index 1875e890fe..a296fb361b 100644
--- a/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py
+++ b/src/calibre/gui2/store/stores/beam_ebooks_de_plugin.py
@@ -14,7 +14,6 @@ except ImportError:
 from contextlib import closing
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/biblio_plugin.py b/src/calibre/gui2/store/stores/biblio_plugin.py
index 63e7096857..d2ade944f5 100644
--- a/src/calibre/gui2/store/stores/biblio_plugin.py
+++ b/src/calibre/gui2/store/stores/biblio_plugin.py
@@ -12,14 +12,16 @@ try:
 except ImportError:
     from urllib import quote_plus
 
+from contextlib import closing
+
+from lxml import html
+
 from calibre import browser
 from calibre.gui2 import open_url
-from calibre.gui2.store.basic_config import BasicStoreConfig
 from calibre.gui2.store import StorePlugin
+from calibre.gui2.store.basic_config import BasicStoreConfig
 from calibre.gui2.store.search_result import SearchResult
 from calibre.gui2.store.web_store_dialog import WebStoreDialog
-from contextlib import closing
-from lxml import html
 
 
 class BiblioStore(BasicStoreConfig, StorePlugin):
diff --git a/src/calibre/gui2/store/stores/bn_plugin.py b/src/calibre/gui2/store/stores/bn_plugin.py
index 82201eddcd..d4eacf5cbc 100644
--- a/src/calibre/gui2/store/stores/bn_plugin.py
+++ b/src/calibre/gui2/store/stores/bn_plugin.py
@@ -5,13 +5,13 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 store_version = 4  # Needed for dynamic plugin loading
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
@@ -22,7 +22,6 @@ from calibre.gui2.store.search_result import SearchResult
 from calibre.gui2.store.web_store_dialog import WebStoreDialog
 
 
-
 def search_bn(query, max_results=10, timeout=60, write_html_to=''):
     url = 'https://www.barnesandnoble.com/s/%s?keyword=%s&store=ebook&view=list' % (query.replace(' ', '-'), quote_plus(query))
 
diff --git a/src/calibre/gui2/store/stores/bubok_portugal_plugin.py b/src/calibre/gui2/store/stores/bubok_portugal_plugin.py
index 603afda8b1..8919e62d5c 100644
--- a/src/calibre/gui2/store/stores/bubok_portugal_plugin.py
+++ b/src/calibre/gui2/store/stores/bubok_portugal_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2014, Rafael Vega <rafavega@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/bubok_publishing_plugin.py b/src/calibre/gui2/store/stores/bubok_publishing_plugin.py
index 5d9da5b50d..3edcecff3c 100644
--- a/src/calibre/gui2/store/stores/bubok_publishing_plugin.py
+++ b/src/calibre/gui2/store/stores/bubok_publishing_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2014, Rafael Vega <rafavega@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/chitanka_plugin.py b/src/calibre/gui2/store/stores/chitanka_plugin.py
index 27da2ef28c..29fa910f3e 100644
--- a/src/calibre/gui2/store/stores/chitanka_plugin.py
+++ b/src/calibre/gui2/store/stores/chitanka_plugin.py
@@ -8,14 +8,14 @@ __copyright__ = '2011, Alex Stanev <alex@stanev.org>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
-    from urllib.parse import quote
     from urllib.error import HTTPError
+    from urllib.parse import quote
 except ImportError:
-    from urllib2 import quote, HTTPError
+    from urllib2 import HTTPError, quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/ebook_nl_plugin.py b/src/calibre/gui2/store/stores/ebook_nl_plugin.py
index 8a3e053d25..a739333660 100644
--- a/src/calibre/gui2/store/stores/ebook_nl_plugin.py
+++ b/src/calibre/gui2/store/stores/ebook_nl_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/ebookpoint_plugin.py b/src/calibre/gui2/store/stores/ebookpoint_plugin.py
index 359dcd40c4..4f6ed24624 100644
--- a/src/calibre/gui2/store/stores/ebookpoint_plugin.py
+++ b/src/calibre/gui2/store/stores/ebookpoint_plugin.py
@@ -10,13 +10,13 @@ __docformat__ = 'restructuredtext en'
 import re
 from base64 import b64encode
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py b/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py
index 9fd8cbebdf..d9259366da 100644
--- a/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py
+++ b/src/calibre/gui2/store/stores/ebookshoppe_uk_plugin.py
@@ -14,7 +14,6 @@ except ImportError:
 from contextlib import closing
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/empik_plugin.py b/src/calibre/gui2/store/stores/empik_plugin.py
index 3280b2f2ce..a75c0c0e2e 100644
--- a/src/calibre/gui2/store/stores/empik_plugin.py
+++ b/src/calibre/gui2/store/stores/empik_plugin.py
@@ -9,13 +9,13 @@ __docformat__ = 'restructuredtext en'
 
 from base64 import b64encode
 from contextlib import closing
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/google_books_plugin.py b/src/calibre/gui2/store/stores/google_books_plugin.py
index f81ca04099..63bcea6b89 100644
--- a/src/calibre/gui2/store/stores/google_books_plugin.py
+++ b/src/calibre/gui2/store/stores/google_books_plugin.py
@@ -8,6 +8,7 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/gutenberg_plugin.py b/src/calibre/gui2/store/stores/gutenberg_plugin.py
index 403d214614..f54748d22d 100644
--- a/src/calibre/gui2/store/stores/gutenberg_plugin.py
+++ b/src/calibre/gui2/store/stores/gutenberg_plugin.py
@@ -11,6 +11,7 @@ try:
 except ImportError:
     from urllib import quote_plus
 
+from css_selectors import Select
 from html5_parser import parse
 from lxml import etree
 
@@ -19,7 +20,6 @@ from calibre.gui2 import open_url
 from calibre.gui2.store import StorePlugin
 from calibre.gui2.store.search_result import SearchResult
 from calibre.gui2.store.web_store_dialog import WebStoreDialog
-from css_selectors import Select
 
 
 def absurl(href):
diff --git a/src/calibre/gui2/store/stores/legimi_plugin.py b/src/calibre/gui2/store/stores/legimi_plugin.py
index 6d23ea4f23..2262f0edf4 100644
--- a/src/calibre/gui2/store/stores/legimi_plugin.py
+++ b/src/calibre/gui2/store/stores/legimi_plugin.py
@@ -9,13 +9,13 @@ __docformat__ = 'restructuredtext en'
 
 from base64 import b64encode
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/libri_de_plugin.py b/src/calibre/gui2/store/stores/libri_de_plugin.py
index f3cbe7bc4a..ec65035726 100644
--- a/src/calibre/gui2/store/stores/libri_de_plugin.py
+++ b/src/calibre/gui2/store/stores/libri_de_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser
diff --git a/src/calibre/gui2/store/stores/litres_plugin.py b/src/calibre/gui2/store/stores/litres_plugin.py
index 5fb5310870..51a231692c 100644
--- a/src/calibre/gui2/store/stores/litres_plugin.py
+++ b/src/calibre/gui2/store/stores/litres_plugin.py
@@ -9,16 +9,18 @@ __docformat__ = 'restructuredtext en'
 
 import random
 import re
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from contextlib import closing
+
 from lxml import etree
 from qt.core import QUrl
 
-from calibre import browser, url_slash_cleaner, prints
+from calibre import browser, prints, url_slash_cleaner
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.gui2 import open_url
 from calibre.gui2.store import StorePlugin
diff --git a/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py b/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py
index 6ab36e07c3..19e9647980 100644
--- a/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py
+++ b/src/calibre/gui2/store/stores/mills_boon_uk_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py b/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py
index dbabd496eb..8ea8dbea80 100644
--- a/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py
+++ b/src/calibre/gui2/store/stores/mobileread/adv_search_builder.py
@@ -1,14 +1,13 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-
 __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 import re
 
-from qt.core import (QDialog, QDialogButtonBox)
+from qt.core import QDialog, QDialogButtonBox
 
 from calibre.gui2.store.stores.mobileread.adv_search_builder_ui import Ui_Dialog
 from calibre.library.caches import CONTAINS_MATCH, EQUALS_MATCH
diff --git a/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py b/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py
index bf3fa4017c..d2f982c203 100644
--- a/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py
+++ b/src/calibre/gui2/store/stores/mobileread/cache_progress_dialog.py
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-
 __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
diff --git a/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py b/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py
index 4a410e684f..e696e9da85 100644
--- a/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py
+++ b/src/calibre/gui2/store/stores/mobileread/cache_update_thread.py
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-
 __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
@@ -11,8 +10,7 @@ from contextlib import closing
 from threading import Thread
 
 from lxml import html
-
-from qt.core import (pyqtSignal, QObject)
+from qt.core import QObject, pyqtSignal
 
 from calibre import browser
 from calibre.gui2.store.search_result import SearchResult
diff --git a/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py b/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py
index 470239ecdd..ed4062d067 100644
--- a/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py
+++ b/src/calibre/gui2/store/stores/mobileread/mobileread_plugin.py
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-
 __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
@@ -9,18 +8,18 @@ __docformat__ = 'restructuredtext en'
 import os
 from threading import Lock
 
-from qt.core import (QUrl, QCoreApplication)
+from qt.core import QCoreApplication, QUrl
 
 from calibre.constants import cache_dir
 from calibre.gui2 import open_url
 from calibre.gui2.store import StorePlugin
 from calibre.gui2.store.basic_config import BasicStoreConfig
 from calibre.gui2.store.search_result import SearchResult
-from calibre.gui2.store.web_store_dialog import WebStoreDialog
-from calibre.gui2.store.stores.mobileread.models import SearchFilter
 from calibre.gui2.store.stores.mobileread.cache_progress_dialog import CacheProgressDialog
 from calibre.gui2.store.stores.mobileread.cache_update_thread import CacheUpdateThread
+from calibre.gui2.store.stores.mobileread.models import SearchFilter
 from calibre.gui2.store.stores.mobileread.store_dialog import MobileReadStoreDialog
+from calibre.gui2.store.web_store_dialog import WebStoreDialog
 
 
 class MobileReadStore(BasicStoreConfig, StorePlugin):
diff --git a/src/calibre/gui2/store/stores/mobileread/models.py b/src/calibre/gui2/store/stores/mobileread/models.py
index 35a391074a..bed3d263a0 100644
--- a/src/calibre/gui2/store/stores/mobileread/models.py
+++ b/src/calibre/gui2/store/stores/mobileread/models.py
@@ -1,16 +1,15 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-
 __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from operator import attrgetter
 
-from qt.core import (Qt, QAbstractItemModel, QModelIndex, pyqtSignal)
+from qt.core import QAbstractItemModel, QModelIndex, Qt, pyqtSignal
 
-from calibre.db.search import _match, CONTAINS_MATCH, EQUALS_MATCH, REGEXP_MATCH
+from calibre.db.search import CONTAINS_MATCH, EQUALS_MATCH, REGEXP_MATCH, _match
 from calibre.utils.config_base import prefs
 from calibre.utils.icu import sort_key
 from calibre.utils.search_query_parser import SearchQueryParser
diff --git a/src/calibre/gui2/store/stores/mobileread/store_dialog.py b/src/calibre/gui2/store/stores/mobileread/store_dialog.py
index c62efd1acd..8bc88d5bc0 100644
--- a/src/calibre/gui2/store/stores/mobileread/store_dialog.py
+++ b/src/calibre/gui2/store/stores/mobileread/store_dialog.py
@@ -1,13 +1,12 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-
 __license__ = 'GPL 3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 
-from qt.core import Qt, QDialog, QIcon, QComboBox
+from qt.core import QComboBox, QDialog, QIcon, Qt
 
 from calibre.gui2.store.stores.mobileread.adv_search_builder import AdvSearchBuilderDialog
 from calibre.gui2.store.stores.mobileread.models import BooksModel
diff --git a/src/calibre/gui2/store/stores/nexto_plugin.py b/src/calibre/gui2/store/stores/nexto_plugin.py
index be746b9bbb..162c6f3f48 100644
--- a/src/calibre/gui2/store/stores/nexto_plugin.py
+++ b/src/calibre/gui2/store/stores/nexto_plugin.py
@@ -8,15 +8,15 @@ __copyright__ = '2011-2023, Tomasz Długosz <tomek3d@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
 import re
-from contextlib import closing
 from base64 import standard_b64encode
+from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/ozon_ru_plugin.py b/src/calibre/gui2/store/stores/ozon_ru_plugin.py
index 57fc4123fc..abc48a7164 100644
--- a/src/calibre/gui2/store/stores/ozon_ru_plugin.py
+++ b/src/calibre/gui2/store/stores/ozon_ru_plugin.py
@@ -8,6 +8,7 @@ __copyright__ = '2011-2013, Roman Mukhin <ramses_ru at hotmail.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
diff --git a/src/calibre/gui2/store/stores/publio_plugin.py b/src/calibre/gui2/store/stores/publio_plugin.py
index b351590ae4..f273b159db 100644
--- a/src/calibre/gui2/store/stores/publio_plugin.py
+++ b/src/calibre/gui2/store/stores/publio_plugin.py
@@ -15,7 +15,6 @@ from base64 import b64encode
 from contextlib import closing
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/rw2010_plugin.py b/src/calibre/gui2/store/stores/rw2010_plugin.py
index ae9173ee30..6a4317678c 100644
--- a/src/calibre/gui2/store/stores/rw2010_plugin.py
+++ b/src/calibre/gui2/store/stores/rw2010_plugin.py
@@ -9,13 +9,13 @@ __docformat__ = 'restructuredtext en'
 
 import re
 from contextlib import closing
+
 try:
     from urllib.parse import urlencode
 except ImportError:
     from urllib import urlencode
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/smashwords_plugin.py b/src/calibre/gui2/store/stores/smashwords_plugin.py
index 4c0da7feea..33f789d471 100644
--- a/src/calibre/gui2/store/stores/smashwords_plugin.py
+++ b/src/calibre/gui2/store/stores/smashwords_plugin.py
@@ -10,13 +10,13 @@ __docformat__ = 'restructuredtext en'
 import random
 import re
 from contextlib import closing
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/swiatebookow_plugin.py b/src/calibre/gui2/store/stores/swiatebookow_plugin.py
index 2e863a36ad..64ebce1465 100644
--- a/src/calibre/gui2/store/stores/swiatebookow_plugin.py
+++ b/src/calibre/gui2/store/stores/swiatebookow_plugin.py
@@ -9,13 +9,13 @@ __docformat__ = 'restructuredtext en'
 
 from base64 import b64encode
 from contextlib import closing
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/virtualo_plugin.py b/src/calibre/gui2/store/stores/virtualo_plugin.py
index d5da180538..9a23544745 100644
--- a/src/calibre/gui2/store/stores/virtualo_plugin.py
+++ b/src/calibre/gui2/store/stores/virtualo_plugin.py
@@ -10,13 +10,13 @@ __docformat__ = 'restructuredtext en'
 import re
 from base64 import b64encode
 from contextlib import closing
+
 try:
     from urllib.parse import quote
 except ImportError:
     from urllib import quote
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/weightless_books_plugin.py b/src/calibre/gui2/store/stores/weightless_books_plugin.py
index 55adb42b7c..27f957feb8 100644
--- a/src/calibre/gui2/store/stores/weightless_books_plugin.py
+++ b/src/calibre/gui2/store/stores/weightless_books_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/stores/woblink_plugin.py b/src/calibre/gui2/store/stores/woblink_plugin.py
index 50aff52a54..197db7a8a7 100644
--- a/src/calibre/gui2/store/stores/woblink_plugin.py
+++ b/src/calibre/gui2/store/stores/woblink_plugin.py
@@ -8,17 +8,17 @@ __copyright__ = '2011-2019, Tomasz Długosz <tomek3d@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
 from base64 import b64encode
+
 try:
-    from urllib.parse import urlencode, quote_plus
+    from urllib.parse import quote_plus, urlencode
 except ImportError:
-    from urllib import urlencode, quote_plus
+    from urllib import quote_plus, urlencode
 
 from lxml import html
 from mechanize import Request
-
 from qt.core import QUrl
 
-from calibre import url_slash_cleaner, browser
+from calibre import browser, url_slash_cleaner
 from calibre.gui2 import open_url
 from calibre.gui2.store import StorePlugin
 from calibre.gui2.store.basic_config import BasicStoreConfig
diff --git a/src/calibre/gui2/store/stores/wolnelektury_plugin.py b/src/calibre/gui2/store/stores/wolnelektury_plugin.py
index 04bcfa8b95..573031993e 100644
--- a/src/calibre/gui2/store/stores/wolnelektury_plugin.py
+++ b/src/calibre/gui2/store/stores/wolnelektury_plugin.py
@@ -8,13 +8,13 @@ __copyright__ = '2012-2023, Tomasz Długosz <tomek3d@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
 from contextlib import closing
+
 try:
     from urllib.parse import quote_plus
 except ImportError:
     from urllib import quote_plus
 
 from lxml import html
-
 from qt.core import QUrl
 
 from calibre import browser, url_slash_cleaner
diff --git a/src/calibre/gui2/store/web_store.py b/src/calibre/gui2/store/web_store.py
index 89a1da1309..14a3be9490 100644
--- a/src/calibre/gui2/store/web_store.py
+++ b/src/calibre/gui2/store/web_store.py
@@ -5,20 +5,14 @@
 import json
 import os
 import shutil
-from qt.core import (
-    QApplication, QHBoxLayout, QIcon, QLabel, QProgressBar, QPushButton, QSize, QUrl,
-    QVBoxLayout, QWidget, pyqtSignal,
-)
-from qt.webengine import (
-    QWebEngineDownloadRequest, QWebEnginePage, QWebEngineProfile, QWebEngineView,
-)
+
+from qt.core import QApplication, QHBoxLayout, QIcon, QLabel, QProgressBar, QPushButton, QSize, QUrl, QVBoxLayout, QWidget, pyqtSignal
+from qt.webengine import QWebEngineDownloadRequest, QWebEnginePage, QWebEngineProfile, QWebEngineView
 
 from calibre import random_user_agent, url_slash_cleaner
 from calibre.constants import STORE_DIALOG_APP_UID, islinux, iswindows
 from calibre.ebooks import BOOK_EXTENSIONS
-from calibre.gui2 import (
-    Application, choose_save_file, error_dialog, gprefs, info_dialog, set_app_uid,
-)
+from calibre.gui2 import Application, choose_save_file, error_dialog, gprefs, info_dialog, set_app_uid
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.listener import send_message_in_process
 from calibre.gui2.main_window import MainWindow
diff --git a/src/calibre/gui2/tag_browser/model.py b/src/calibre/gui2/tag_browser/model.py
index 96f049bfe0..ba9721e230 100644
--- a/src/calibre/gui2/tag_browser/model.py
+++ b/src/calibre/gui2/tag_browser/model.py
@@ -9,24 +9,20 @@ import copy
 import os
 import traceback
 from collections import OrderedDict, namedtuple
-from qt.core import (
-    QAbstractItemModel, QFont, QIcon, QMimeData, QModelIndex, QObject, Qt, pyqtSignal,
-)
+
+from qt.core import QAbstractItemModel, QFont, QIcon, QMimeData, QModelIndex, QObject, Qt, pyqtSignal
 
 from calibre.constants import config_dir
 from calibre.db.categories import Tag, category_display_order
 from calibre.ebooks.metadata import rating_to_stars
-from calibre.gui2 import (
-    config, error_dialog, file_icon_provider, gprefs, question_dialog,
-)
+from calibre.gui2 import config, error_dialog, file_icon_provider, gprefs, question_dialog
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.library.field_metadata import category_icon_map
 from calibre.utils.config import prefs, tweaks
 from calibre.utils.formatter import EvalFormatter
-from calibre.utils.icu import (
-    collation_order_for_partitioning, contains, lower, lower as icu_lower,
-    primary_contains, primary_strcmp, sort_key, strcmp, upper as icu_upper,
-)
+from calibre.utils.icu import collation_order_for_partitioning, contains, lower, primary_contains, primary_strcmp, sort_key, strcmp
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 from calibre.utils.serialize import json_dumps, json_loads
 from polyglot.builtins import iteritems, itervalues
 
diff --git a/src/calibre/gui2/tag_browser/ui.py b/src/calibre/gui2/tag_browser/ui.py
index 7ff8419ec7..56837b1fc9 100644
--- a/src/calibre/gui2/tag_browser/ui.py
+++ b/src/calibre/gui2/tag_browser/ui.py
@@ -8,9 +8,24 @@ __docformat__ = 'restructuredtext en'
 import copy
 import textwrap
 from functools import partial
+
 from qt.core import (
-    QAction, QActionGroup, QComboBox, QDialog, QFrame, QHBoxLayout, QIcon, QLabel,
-    QLineEdit, QMenu, QSizePolicy, Qt, QTimer, QToolButton, QVBoxLayout, QWidget,
+    QAction,
+    QActionGroup,
+    QComboBox,
+    QDialog,
+    QFrame,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QMenu,
+    QSizePolicy,
+    Qt,
+    QTimer,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
     pyqtSignal,
 )
 
diff --git a/src/calibre/gui2/tag_browser/view.py b/src/calibre/gui2/tag_browser/view.py
index 53ca5edbef..623b7db857 100644
--- a/src/calibre/gui2/tag_browser/view.py
+++ b/src/calibre/gui2/tag_browser/view.py
@@ -11,26 +11,43 @@ import traceback
 from collections import defaultdict
 from contextlib import suppress
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QApplication, QBrush, QColor, QCursor, QDialog, QDrag, QFont, QIcon,
-    QLinearGradient, QMenu, QModelIndex, QPalette, QPen, QPoint, QPointF, QRect, QSize,
-    QStyle, QStyledItemDelegate, QStyleOptionViewItem, Qt, QTimer, QToolTip, QTreeView,
+    QAbstractItemView,
+    QApplication,
+    QBrush,
+    QColor,
+    QCursor,
+    QDialog,
+    QDrag,
+    QFont,
+    QIcon,
+    QLinearGradient,
+    QMenu,
+    QModelIndex,
+    QPalette,
+    QPen,
+    QPoint,
+    QPointF,
+    QRect,
+    QSize,
+    QStyle,
+    QStyledItemDelegate,
+    QStyleOptionViewItem,
+    Qt,
+    QTimer,
+    QToolTip,
+    QTreeView,
     pyqtSignal,
 )
 
 from calibre import sanitize_file_name
 from calibre.constants import config_dir
 from calibre.ebooks.metadata import rating_to_stars
-from calibre.gui2 import (
-    FunctionDispatcher, choose_files, config, empty_index, gprefs, pixmap_to_data,
-    question_dialog, rating_font, safe_open_url,
-)
-from calibre.gui2.dialogs.edit_category_notes import EditNoteDialog
+from calibre.gui2 import FunctionDispatcher, choose_files, config, empty_index, gprefs, pixmap_to_data, question_dialog, rating_font, safe_open_url
 from calibre.gui2.complete2 import EditWithComplete
-from calibre.gui2.tag_browser.model import (
-    COUNT_ROLE, DRAG_IMAGE_ROLE, TAG_SEARCH_STATES, TagsModel, TagTreeItem,
-    rename_only_in_vl_question,
-)
+from calibre.gui2.dialogs.edit_category_notes import EditNoteDialog
+from calibre.gui2.tag_browser.model import COUNT_ROLE, DRAG_IMAGE_ROLE, TAG_SEARCH_STATES, TagsModel, TagTreeItem, rename_only_in_vl_question
 from calibre.gui2.widgets import EnLineEdit
 from calibre.utils.icu import sort_key
 from calibre.utils.serialize import json_loads
diff --git a/src/calibre/gui2/tag_mapper.py b/src/calibre/gui2/tag_mapper.py
index 001aa2324f..a50105b853 100644
--- a/src/calibre/gui2/tag_mapper.py
+++ b/src/calibre/gui2/tag_mapper.py
@@ -4,11 +4,32 @@
 
 import textwrap
 from collections import OrderedDict
+
 from qt.core import (
-    QAbstractItemView, QComboBox, QDialog, QDialogButtonBox, QHBoxLayout, QIcon,
-    QInputDialog, QItemSelectionModel, QLabel, QLineEdit, QListWidget, QListWidgetItem,
-    QMenu, QPalette, QPushButton, QSize, QStaticText, QStyle, QStyledItemDelegate, Qt,
-    QToolButton, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QItemSelectionModel,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QPalette,
+    QPushButton,
+    QSize,
+    QStaticText,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.ebooks.metadata.tag_mapper import compile_pat, map_tags
diff --git a/src/calibre/gui2/threaded_jobs.py b/src/calibre/gui2/threaded_jobs.py
index 793e24a11b..57bc175ada 100644
--- a/src/calibre/gui2/threaded_jobs.py
+++ b/src/calibre/gui2/threaded_jobs.py
@@ -5,12 +5,15 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, time, tempfile, json
-from threading import Thread, RLock, Event
+import json
+import os
+import tempfile
+import time
+from threading import Event, RLock, Thread
 
+from calibre.ptempfile import base_dir
 from calibre.utils.ipc.job import BaseJob
 from calibre.utils.logging import GUILog
-from calibre.ptempfile import base_dir
 from polyglot.queue import Queue
 
 
@@ -164,6 +167,7 @@ class ThreadedJobWorker(Thread):
             self.job.start_work()
         except:
             import traceback
+
             from calibre import prints
             prints('Job had unhandled exception:', self.job.description)
             traceback.print_exc()
diff --git a/src/calibre/gui2/throbber.py b/src/calibre/gui2/throbber.py
index f890d21f99..89b6eccea9 100644
--- a/src/calibre/gui2/throbber.py
+++ b/src/calibre/gui2/throbber.py
@@ -7,8 +7,20 @@ __docformat__ = 'restructuredtext en'
 
 
 from qt.core import (
-    QToolButton, QSize, QPropertyAnimation, Qt, QMetaObject, pyqtProperty, QSizePolicy,
-    QWidget, QIcon, QPainter, QStyleOptionToolButton, QStyle, QAbstractAnimation)
+    QAbstractAnimation,
+    QIcon,
+    QMetaObject,
+    QPainter,
+    QPropertyAnimation,
+    QSize,
+    QSizePolicy,
+    QStyle,
+    QStyleOptionToolButton,
+    Qt,
+    QToolButton,
+    QWidget,
+    pyqtProperty,
+)
 
 from calibre.gui2 import config
 
diff --git a/src/calibre/gui2/toc/location.py b/src/calibre/gui2/toc/location.py
index e67eec1527..313ff1b5c0 100644
--- a/src/calibre/gui2/toc/location.py
+++ b/src/calibre/gui2/toc/location.py
@@ -7,15 +7,33 @@ import os
 import sys
 import weakref
 from functools import lru_cache
+
 from qt.core import (
-    QApplication, QByteArray, QFrame, QGridLayout, QIcon, QLabel, QLineEdit,
-    QListWidget, QPushButton, QSize, QSplitter, Qt, QUrl, QVBoxLayout, QWidget,
+    QApplication,
+    QByteArray,
+    QFrame,
+    QGridLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QPushButton,
+    QSize,
+    QSplitter,
+    Qt,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
     pyqtSignal,
 )
 from qt.webengine import (
-    QWebEnginePage, QWebEngineProfile, QWebEngineScript,
-    QWebEngineUrlRequestInterceptor, QWebEngineUrlRequestJob,
-    QWebEngineUrlSchemeHandler, QWebEngineView,
+    QWebEnginePage,
+    QWebEngineProfile,
+    QWebEngineScript,
+    QWebEngineUrlRequestInterceptor,
+    QWebEngineUrlRequestJob,
+    QWebEngineUrlSchemeHandler,
+    QWebEngineView,
 )
 
 from calibre.constants import FAKE_HOST, FAKE_PROTOCOL
diff --git a/src/calibre/gui2/toc/main.py b/src/calibre/gui2/toc/main.py
index 6c9734c4b8..4ead1e444a 100644
--- a/src/calibre/gui2/toc/main.py
+++ b/src/calibre/gui2/toc/main.py
@@ -7,20 +7,42 @@ import sys
 import tempfile
 import textwrap
 from functools import partial
-from qt.core import (
-    QAbstractItemView, QCheckBox, QCursor, QDialog, QDialogButtonBox, QEvent, QFrame,
-    QGridLayout, QIcon, QInputDialog, QItemSelectionModel, QKeySequence, QLabel, QMenu,
-    QPushButton, QScrollArea, QSize, QSizePolicy, QStackedWidget, Qt, QTimer,
-    QToolButton, QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 from time import monotonic
 
+from qt.core import (
+    QAbstractItemView,
+    QCheckBox,
+    QCursor,
+    QDialog,
+    QDialogButtonBox,
+    QEvent,
+    QFrame,
+    QGridLayout,
+    QIcon,
+    QInputDialog,
+    QItemSelectionModel,
+    QKeySequence,
+    QLabel,
+    QMenu,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QStackedWidget,
+    Qt,
+    QTimer,
+    QToolButton,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre.constants import TOC_DIALOG_APP_UID, islinux, ismacos, iswindows
 from calibre.ebooks.oeb.polish.container import AZW3Container, get_container
-from calibre.ebooks.oeb.polish.toc import (
-    TOC, add_id, commit_toc, from_files, from_links, from_xpaths, get_toc,
-)
+from calibre.ebooks.oeb.polish.toc import TOC, add_id, commit_toc, from_files, from_links, from_xpaths, get_toc
 from calibre.gui2 import Application, error_dialog, info_dialog, set_app_uid
 from calibre.gui2.convert.xpath_wizard import XPathEdit
 from calibre.gui2.progress_indicator import ProgressIndicator
@@ -29,7 +51,8 @@ from calibre.ptempfile import reset_base_dir
 from calibre.startup import connect_lambda
 from calibre.utils.config import JSONConfig
 from calibre.utils.filenames import atomic_rename
-from calibre.utils.icu import lower as icu_lower, upper as icu_upper
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 from calibre.utils.logging import GUILog
 
 ICON_SIZE = 24
diff --git a/src/calibre/gui2/tools.py b/src/calibre/gui2/tools.py
index 9159eed9ea..994766415a 100644
--- a/src/calibre/gui2/tools.py
+++ b/src/calibre/gui2/tools.py
@@ -13,17 +13,22 @@ import os
 
 from qt.core import QDialog, QProgressDialog, QTimer
 
-from calibre.ptempfile import PersistentTemporaryFile
-from calibre.gui2 import warning_dialog, question_dialog
-from calibre.gui2.convert.single import Config as SingleConfig
-from calibre.gui2.convert.bulk import BulkConfig
-from calibre.gui2.convert.metadata import create_opf_file, create_cover_file
 from calibre.customize.conversion import OptionRecommendation
-from calibre.utils.config import prefs
 from calibre.ebooks.conversion.config import (
-        GuiRecommendations, load_defaults, load_specifics, save_specifics,
-        get_input_format_for_book, NoSupportedInputFormats)
+    GuiRecommendations,
+    NoSupportedInputFormats,
+    get_input_format_for_book,
+    load_defaults,
+    load_specifics,
+    save_specifics,
+)
+from calibre.gui2 import question_dialog, warning_dialog
 from calibre.gui2.convert import bulk_defaults_for_input_format
+from calibre.gui2.convert.bulk import BulkConfig
+from calibre.gui2.convert.metadata import create_cover_file, create_opf_file
+from calibre.gui2.convert.single import Config as SingleConfig
+from calibre.ptempfile import PersistentTemporaryFile
+from calibre.utils.config import prefs
 from polyglot.builtins import as_bytes
 
 
diff --git a/src/calibre/gui2/trash.py b/src/calibre/gui2/trash.py
index d10101c9e2..1b98465d7f 100644
--- a/src/calibre/gui2/trash.py
+++ b/src/calibre/gui2/trash.py
@@ -4,16 +4,34 @@
 import time
 import traceback
 from operator import attrgetter
-from qt.core import (
-    QAbstractItemView, QDialogButtonBox, QHBoxLayout, QIcon, QLabel, QListWidget,
-    QListWidgetItem, QMenu, QPainter, QPalette, QPixmap, QRectF, QSize, QSpinBox,
-    QStyle, QStyledItemDelegate, Qt, QTabWidget, QVBoxLayout, pyqtSignal,
-)
 from typing import Iterator, List
 
+from qt.core import (
+    QAbstractItemView,
+    QDialogButtonBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QPainter,
+    QPalette,
+    QPixmap,
+    QRectF,
+    QSize,
+    QSpinBox,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTabWidget,
+    QVBoxLayout,
+    pyqtSignal,
+)
+
 from calibre import fit_image
 from calibre.db.constants import DEFAULT_TRASH_EXPIRY_TIME_SECONDS, TrashEntry
-from calibre.gui2 import error_dialog, choose_dir, choose_save_file
+from calibre.gui2 import choose_dir, choose_save_file, error_dialog
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.widgets import BusyCursor
 from calibre.gui2.widgets2 import Dialog
diff --git a/src/calibre/gui2/tts/develop.py b/src/calibre/gui2/tts/develop.py
index 03bd8117d9..85ee75f412 100644
--- a/src/calibre/gui2/tts/develop.py
+++ b/src/calibre/gui2/tts/develop.py
@@ -4,10 +4,8 @@
 
 import re
 from itertools import count
-from qt.core import (
-    QDialogButtonBox, QLabel, QMainWindow, Qt, QTimer, QVBoxLayout, QWidget,
-    pyqtSignal
-)
+
+from qt.core import QDialogButtonBox, QLabel, QMainWindow, Qt, QTimer, QVBoxLayout, QWidget, pyqtSignal
 
 from calibre.gui2 import Application
 
diff --git a/src/calibre/gui2/tts/implementation.py b/src/calibre/gui2/tts/implementation.py
index f72d6ace18..434b764a3b 100644
--- a/src/calibre/gui2/tts/implementation.py
+++ b/src/calibre/gui2/tts/implementation.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
-from calibre.constants import iswindows, ismacos
+from calibre.constants import ismacos, iswindows
 
 if iswindows:
     from calibre.utils.config_base import tweaks
diff --git a/src/calibre/gui2/tts/linux_config.py b/src/calibre/gui2/tts/linux_config.py
index e331437d68..e581430438 100644
--- a/src/calibre/gui2/tts/linux_config.py
+++ b/src/calibre/gui2/tts/linux_config.py
@@ -2,10 +2,20 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
+
 from qt.core import (
-    QAbstractItemView, QAbstractTableModel, QByteArray, QComboBox, QFontMetrics,
-    QFormLayout, QItemSelectionModel, QSlider, QSortFilterProxyModel, Qt, QTableView,
-    QWidget
+    QAbstractItemView,
+    QAbstractTableModel,
+    QByteArray,
+    QComboBox,
+    QFontMetrics,
+    QFormLayout,
+    QItemSelectionModel,
+    QSlider,
+    QSortFilterProxyModel,
+    Qt,
+    QTableView,
+    QWidget,
 )
 
 from calibre.gui2.widgets import BusyCursor
diff --git a/src/calibre/gui2/tts/macos.py b/src/calibre/gui2/tts/macos.py
index 434f12ebf2..37f3a3cc87 100644
--- a/src/calibre/gui2/tts/macos.py
+++ b/src/calibre/gui2/tts/macos.py
@@ -46,7 +46,7 @@ class Client:
     shutdown = __del__
 
     def handle_message(self, message_type, data):
-        from calibre_extensions.cocoa import MARK, END
+        from calibre_extensions.cocoa import END, MARK
         event = None
         if message_type == MARK:
             self.last_mark = data
diff --git a/src/calibre/gui2/tts/macos_config.py b/src/calibre/gui2/tts/macos_config.py
index ee03c8df2a..fd69fa4464 100644
--- a/src/calibre/gui2/tts/macos_config.py
+++ b/src/calibre/gui2/tts/macos_config.py
@@ -2,9 +2,19 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
+
 from qt.core import (
-    QAbstractItemView, QAbstractTableModel, QByteArray, QFontMetrics, QFormLayout,
-    QItemSelectionModel, QSlider, QSortFilterProxyModel, Qt, QTableView, QWidget
+    QAbstractItemView,
+    QAbstractTableModel,
+    QByteArray,
+    QFontMetrics,
+    QFormLayout,
+    QItemSelectionModel,
+    QSlider,
+    QSortFilterProxyModel,
+    Qt,
+    QTableView,
+    QWidget,
 )
 
 from calibre.gui2.widgets import BusyCursor
diff --git a/src/calibre/gui2/tts/windows.py b/src/calibre/gui2/tts/windows.py
index ce1fe605ba..a3e3c78269 100644
--- a/src/calibre/gui2/tts/windows.py
+++ b/src/calibre/gui2/tts/windows.py
@@ -3,10 +3,11 @@
 
 from functools import partial
 
-from calibre.utils.windows.winspeech import WinSpeech, Error, MarkReached, MediaStateChanged, MediaState
+from calibre.utils.windows.winspeech import Error, MarkReached, MediaState, MediaStateChanged, WinSpeech
 
 from .common import Event, EventType
 
+
 def split_into_chunks(marked_text, chunk_size):
     chunk = []
     tlen = 0
diff --git a/src/calibre/gui2/tts/windows_config.py b/src/calibre/gui2/tts/windows_config.py
index a3157cd06e..c044408a8b 100644
--- a/src/calibre/gui2/tts/windows_config.py
+++ b/src/calibre/gui2/tts/windows_config.py
@@ -2,10 +2,20 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
+
 from qt.core import (
-    QAbstractItemView, QAbstractTableModel, QByteArray, QComboBox, QFontMetrics,
-    QFormLayout, QItemSelectionModel, QSlider, QSortFilterProxyModel, Qt, QTableView,
-    QWidget
+    QAbstractItemView,
+    QAbstractTableModel,
+    QByteArray,
+    QComboBox,
+    QFontMetrics,
+    QFormLayout,
+    QItemSelectionModel,
+    QSlider,
+    QSortFilterProxyModel,
+    Qt,
+    QTableView,
+    QWidget,
 )
 
 from calibre.gui2.widgets import BusyCursor
diff --git a/src/calibre/gui2/tts/windows_sapi.py b/src/calibre/gui2/tts/windows_sapi.py
index 68444df44d..853271165d 100644
--- a/src/calibre/gui2/tts/windows_sapi.py
+++ b/src/calibre/gui2/tts/windows_sapi.py
@@ -2,8 +2,8 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from time import monotonic
 from threading import Thread
+from time import monotonic
 from typing import NamedTuple
 
 from calibre import prepare_string_for_xml
@@ -146,9 +146,7 @@ class Client:
             self.dispatch_on_main_thread(self.handle_events)
 
     def handle_events(self):
-        from calibre_extensions.winsapi import (
-            SPEI_END_INPUT_STREAM, SPEI_START_INPUT_STREAM, SPEI_TTS_BOOKMARK
-        )
+        from calibre_extensions.winsapi import SPEI_END_INPUT_STREAM, SPEI_START_INPUT_STREAM, SPEI_TTS_BOOKMARK
         c = self.current_callback
 
         for (stream_number, event_type, event_data) in self.sp_voice.get_events():
@@ -193,9 +191,7 @@ class Client:
             raise
 
     def speak(self, text, is_xml=False, want_events=True, purge=True):
-        from calibre_extensions.winsapi import (
-            SPF_ASYNC, SPF_IS_NOT_XML, SPF_PURGEBEFORESPEAK, SPF_IS_XML
-        )
+        from calibre_extensions.winsapi import SPF_ASYNC, SPF_IS_NOT_XML, SPF_IS_XML, SPF_PURGEBEFORESPEAK
         flags = SPF_IS_XML if is_xml else SPF_IS_NOT_XML
         if purge:
             flags |= SPF_PURGEBEFORESPEAK
diff --git a/src/calibre/gui2/tts/windows_sapi_config.py b/src/calibre/gui2/tts/windows_sapi_config.py
index 79e731d636..da0ebe6573 100644
--- a/src/calibre/gui2/tts/windows_sapi_config.py
+++ b/src/calibre/gui2/tts/windows_sapi_config.py
@@ -2,10 +2,20 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
+
 from qt.core import (
-    QAbstractItemView, QAbstractTableModel, QByteArray, QComboBox, QFontMetrics,
-    QFormLayout, QItemSelectionModel, QSlider, QSortFilterProxyModel, Qt, QTableView,
-    QWidget
+    QAbstractItemView,
+    QAbstractTableModel,
+    QByteArray,
+    QComboBox,
+    QFontMetrics,
+    QFormLayout,
+    QItemSelectionModel,
+    QSlider,
+    QSortFilterProxyModel,
+    Qt,
+    QTableView,
+    QWidget,
 )
 
 from calibre.gui2.widgets import BusyCursor
diff --git a/src/calibre/gui2/tweak_book/__init__.py b/src/calibre/gui2/tweak_book/__init__.py
index c480b8eb65..f82558e354 100644
--- a/src/calibre/gui2/tweak_book/__init__.py
+++ b/src/calibre/gui2/tweak_book/__init__.py
@@ -5,10 +5,10 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import string
-from polyglot.builtins import iteritems
 
-from calibre.utils.config import JSONConfig
 from calibre.spell.dictionary import Dictionaries, parse_lang_code
+from calibre.utils.config import JSONConfig
+from polyglot.builtins import iteritems
 
 CONTAINER_DND_MIMETYPE = 'application/x-calibre-container-name-list'
 tprefs = JSONConfig('tweak_book_gui')
diff --git a/src/calibre/gui2/tweak_book/boss.py b/src/calibre/gui2/tweak_book/boss.py
index 0388c84314..eb297da47e 100644
--- a/src/calibre/gui2/tweak_book/boss.py
+++ b/src/calibre/gui2/tweak_book/boss.py
@@ -8,57 +8,76 @@ import subprocess
 import sys
 import tempfile
 from functools import partial, wraps
+
 from qt.core import (
-    QApplication, QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon,
-    QInputDialog, QLabel, QMimeData, QObject, QSize, Qt, QTimer, QUrl, QVBoxLayout,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QIcon,
+    QInputDialog,
+    QLabel,
+    QMimeData,
+    QObject,
+    QSize,
+    Qt,
+    QTimer,
+    QUrl,
+    QVBoxLayout,
     pyqtSignal,
 )
 
 from calibre import isbytestring, prints
 from calibre.constants import cache_dir, islinux, ismacos, iswindows
 from calibre.ebooks.oeb.base import urlnormalize
-from calibre.ebooks.oeb.polish.container import (
-    OEB_DOCS, OEB_STYLES, clone_container, get_container as _gc, guess_type,
-)
+from calibre.ebooks.oeb.polish.container import OEB_DOCS, OEB_STYLES, clone_container, guess_type
+from calibre.ebooks.oeb.polish.container import get_container as _gc
 from calibre.ebooks.oeb.polish.cover import mark_as_cover, mark_as_titlepage, set_cover
 from calibre.ebooks.oeb.polish.css import filter_css, rename_class
 from calibre.ebooks.oeb.polish.main import SUPPORTED, tweak_polish
 from calibre.ebooks.oeb.polish.pretty import fix_all_html, pretty_all
-from calibre.ebooks.oeb.polish.replace import (
-    get_recommended_folders, rationalize_folders, rename_files, replace_file,
-)
+from calibre.ebooks.oeb.polish.replace import get_recommended_folders, rationalize_folders, rename_files, replace_file
 from calibre.ebooks.oeb.polish.split import AbortError, merge, multisplit, split
-from calibre.ebooks.oeb.polish.toc import (
-    create_inline_toc, mark_as_nav, remove_names_from_toc,
-)
-from calibre.ebooks.oeb.polish.utils import (
-    link_stylesheets, setup_css_parser_serialization as scs,
-)
+from calibre.ebooks.oeb.polish.toc import create_inline_toc, mark_as_nav, remove_names_from_toc
+from calibre.ebooks.oeb.polish.utils import link_stylesheets
+from calibre.ebooks.oeb.polish.utils import setup_css_parser_serialization as scs
 from calibre.gui2 import (
-    add_to_recent_docs, choose_dir, choose_files, choose_save_file, error_dialog,
-    info_dialog, open_url, question_dialog, sanitize_env_vars, warning_dialog,
+    add_to_recent_docs,
+    choose_dir,
+    choose_files,
+    choose_save_file,
+    error_dialog,
+    info_dialog,
+    open_url,
+    question_dialog,
+    sanitize_env_vars,
+    warning_dialog,
 )
 from calibre.gui2.dialogs.confirm_delete import confirm
-from calibre.gui2.tweak_book import (
-    actions, current_container, dictionaries, editor_name, editors, set_book_locale,
-    set_current_container, tprefs,
-)
+from calibre.gui2.tweak_book import actions, current_container, dictionaries, editor_name, editors, set_book_locale, set_current_container, tprefs
 from calibre.gui2.tweak_book.completion.worker import completion_worker
 from calibre.gui2.tweak_book.editor import editor_from_syntax, syntax_from_mime
 from calibre.gui2.tweak_book.editor.insert_resource import NewBook, get_resource_data
 from calibre.gui2.tweak_book.file_list import FILE_COPY_MIME, NewFileDialog
 from calibre.gui2.tweak_book.preferences import Preferences
 from calibre.gui2.tweak_book.preview import parse_worker
-from calibre.gui2.tweak_book.save import (
-    SaveManager, find_first_existing_ancestor, save_container,
-)
+from calibre.gui2.tweak_book.save import SaveManager, find_first_existing_ancestor, save_container
 from calibre.gui2.tweak_book.search import run_search, validate_search_request
-from calibre.gui2.tweak_book.spell import find_next as find_next_word, find_next_error
+from calibre.gui2.tweak_book.spell import find_next as find_next_word
+from calibre.gui2.tweak_book.spell import find_next_error
 from calibre.gui2.tweak_book.toc import TOCEditor
 from calibre.gui2.tweak_book.undo import GlobalUndoHistory
 from calibre.gui2.tweak_book.widgets import (
-    AddCover, FilterCSS, ImportForeign, InsertLink, InsertSemantics, InsertTag,
-    MultiSplit, QuickOpen, RationalizeFolders,
+    AddCover,
+    FilterCSS,
+    ImportForeign,
+    InsertLink,
+    InsertSemantics,
+    InsertTag,
+    MultiSplit,
+    QuickOpen,
+    RationalizeFolders,
 )
 from calibre.gui2.widgets import BusyCursor
 from calibre.ptempfile import PersistentTemporaryDirectory, TemporaryDirectory
@@ -214,9 +233,7 @@ class Boss(QObject):
             for ed in itervalues(editors):
                 ed.apply_settings(dictionaries_changed=p.dictionaries_changed)
         if orig_spell != tprefs['inline_spell_check']:
-            from calibre.gui2.tweak_book.editor.syntax.html import (
-                refresh_spell_check_status,
-            )
+            from calibre.gui2.tweak_book.editor.syntax.html import refresh_spell_check_status
             refresh_spell_check_status()
             for ed in itervalues(editors):
                 try:
@@ -502,9 +519,7 @@ class Boss(QObject):
             return
         added_name = self.do_add_file(d.file_name, d.file_data, using_template=d.using_template, edit_file=True)
         if d.file_name.rpartition('.')[2].lower() in ('ttf', 'otf', 'woff'):
-            from calibre.gui2.tweak_book.manage_fonts import (
-                show_font_face_rule_for_font_file,
-            )
+            from calibre.gui2.tweak_book.manage_fonts import show_font_face_rule_for_font_file
             show_font_face_rule_for_font_file(d.file_data, added_name, self.gui)
 
     def do_add_file(self, file_name, data, using_template=False, edit_file=False):
@@ -567,9 +582,7 @@ class Boss(QObject):
             self.set_modified()
             completion_worker().clear_caches('names')
             if added_fonts:
-                from calibre.gui2.tweak_book.manage_fonts import (
-                    show_font_face_rule_for_font_files,
-                )
+                from calibre.gui2.tweak_book.manage_fonts import show_font_face_rule_for_font_files
                 show_font_face_rule_for_font_files(c, added_fonts, self.gui)
 
     def add_cover(self):
@@ -1219,9 +1232,7 @@ class Boss(QObject):
                     'No file with the name %s was found in the book') % target, show=True)
 
     def editor_class_clicked(self, class_data):
-        from calibre.gui2.tweak_book.jump_to_class import (
-            NoMatchingRuleFound, NoMatchingTagFound, find_first_matching_rule,
-        )
+        from calibre.gui2.tweak_book.jump_to_class import NoMatchingRuleFound, NoMatchingTagFound, find_first_matching_rule
         ed = self.gui.central.current_editor
         name = editor_name(ed)
         try:
@@ -1638,9 +1649,7 @@ class Boss(QObject):
     def compress_images(self):
         if not self.ensure_book(_('You must first open a book in order to compress images.')):
             return
-        from calibre.gui2.tweak_book.polish import (
-            CompressImages, CompressImagesProgress, show_report,
-        )
+        from calibre.gui2.tweak_book.polish import CompressImages, CompressImagesProgress, show_report
         d = CompressImages(self.gui)
         if d.exec() == QDialog.DialogCode.Accepted:
             with BusyCursor():
diff --git a/src/calibre/gui2/tweak_book/char_select.py b/src/calibre/gui2/tweak_book/char_select.py
index 034a04ad21..0cdfff965d 100644
--- a/src/calibre/gui2/tweak_book/char_select.py
+++ b/src/calibre/gui2/tweak_book/char_select.py
@@ -8,11 +8,33 @@ import re
 import textwrap
 from bisect import bisect
 from functools import partial
+
 from qt.core import (
-    QAbstractItemModel, QAbstractItemView, QAbstractListModel, QApplication, QCheckBox,
-    QDialogButtonBox, QGridLayout, QHBoxLayout, QIcon, QInputMethodEvent, QLabel,
-    QListView, QMenu, QMimeData, QModelIndex, QPen, QPushButton, QSize, QSizePolicy,
-    QSplitter, QStyledItemDelegate, Qt, QToolButton, QTreeView, pyqtSignal,
+    QAbstractItemModel,
+    QAbstractItemView,
+    QAbstractListModel,
+    QApplication,
+    QCheckBox,
+    QDialogButtonBox,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QInputMethodEvent,
+    QLabel,
+    QListView,
+    QMenu,
+    QMimeData,
+    QModelIndex,
+    QPen,
+    QPushButton,
+    QSize,
+    QSizePolicy,
+    QSplitter,
+    QStyledItemDelegate,
+    Qt,
+    QToolButton,
+    QTreeView,
+    pyqtSignal,
 )
 
 from calibre.gui2.tweak_book import tprefs
diff --git a/src/calibre/gui2/tweak_book/check.py b/src/calibre/gui2/tweak_book/check.py
index 192d8d0f51..6a228b89ef 100644
--- a/src/calibre/gui2/tweak_book/check.py
+++ b/src/calibre/gui2/tweak_book/check.py
@@ -7,12 +7,22 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import sys
 
 from qt.core import (
-     QIcon, Qt, QSplitter, QListWidget, QTextBrowser, QPalette, QMenu,
-     QListWidgetItem, pyqtSignal, QApplication, QStyledItemDelegate,
-     QAbstractItemView)
+    QAbstractItemView,
+    QApplication,
+    QIcon,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QPalette,
+    QSplitter,
+    QStyledItemDelegate,
+    Qt,
+    QTextBrowser,
+    pyqtSignal,
+)
 
-from calibre.ebooks.oeb.polish.check.base import WARN, INFO, DEBUG, ERROR, CRITICAL
-from calibre.ebooks.oeb.polish.check.main import run_checks, fix_errors
+from calibre.ebooks.oeb.polish.check.base import CRITICAL, DEBUG, ERROR, INFO, WARN
+from calibre.ebooks.oeb.polish.check.main import fix_errors, run_checks
 from calibre.gui2 import NO_URL_FORMATTING, safe_open_url
 from calibre.gui2.tweak_book import tprefs
 from calibre.gui2.widgets import BusyCursor
diff --git a/src/calibre/gui2/tweak_book/check_links.py b/src/calibre/gui2/tweak_book/check_links.py
index 02dca7da12..d5738c5f21 100644
--- a/src/calibre/gui2/tweak_book/check_links.py
+++ b/src/calibre/gui2/tweak_book/check_links.py
@@ -2,16 +2,27 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 from collections import defaultdict
-from qt.core import (
-    QCheckBox, QDialogButtonBox, QHBoxLayout, QIcon, QInputDialog, QLabel, QProgressBar,
-    QSizePolicy, QStackedWidget, Qt, QTextBrowser, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 
-from calibre.gui2 import error_dialog
-from calibre.gui2.tweak_book import (
-    current_container, editors, set_current_container, tprefs,
+from qt.core import (
+    QCheckBox,
+    QDialogButtonBox,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QLabel,
+    QProgressBar,
+    QSizePolicy,
+    QStackedWidget,
+    Qt,
+    QTextBrowser,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
+
+from calibre.gui2 import error_dialog
+from calibre.gui2.tweak_book import current_container, editors, set_current_container, tprefs
 from calibre.gui2.tweak_book.boss import get_boss
 from calibre.gui2.tweak_book.widgets import Dialog
 from calibre.utils.localization import ngettext
diff --git a/src/calibre/gui2/tweak_book/completion/basic.py b/src/calibre/gui2/tweak_book/completion/basic.py
index 3962951bb6..105ba00015 100644
--- a/src/calibre/gui2/tweak_book/completion/basic.py
+++ b/src/calibre/gui2/tweak_book/completion/basic.py
@@ -4,22 +4,22 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
+from collections import OrderedDict, namedtuple
 from threading import Event
-from collections import namedtuple, OrderedDict
 
-from qt.core import QObject, pyqtSignal, Qt
+from qt.core import QObject, Qt, pyqtSignal
 
 from calibre import prepare_string_for_xml
 from calibre.ebooks.oeb.polish.container import OEB_STYLES, name_to_href
-from calibre.ebooks.oeb.polish.utils import OEB_FONTS
 from calibre.ebooks.oeb.polish.parsing import parse
 from calibre.ebooks.oeb.polish.report import description_for_anchor
+from calibre.ebooks.oeb.polish.utils import OEB_FONTS
 from calibre.gui2 import is_gui_thread
 from calibre.gui2.tweak_book import current_container, editors
-from calibre.gui2.tweak_book.completion.utils import control, data, DataError
+from calibre.gui2.tweak_book.completion.utils import DataError, control, data
+from calibre.utils.icu import numeric_sort_key
 from calibre.utils.ipc import eintr_retry_call
 from calibre.utils.matcher import Matcher
-from calibre.utils.icu import numeric_sort_key
 from polyglot.builtins import iteritems, itervalues
 
 Request = namedtuple('Request', 'id type data query')
diff --git a/src/calibre/gui2/tweak_book/completion/popup.py b/src/calibre/gui2/tweak_book/completion/popup.py
index e57eb01c5f..58561459ea 100644
--- a/src/calibre/gui2/tweak_book/completion/popup.py
+++ b/src/calibre/gui2/tweak_book/completion/popup.py
@@ -7,10 +7,9 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import textwrap
 from math import ceil
 
-from qt.core import (
-    QWidget, Qt, QStaticText, QTextOption, QSize, QPainter, QTimer, QPalette, QEvent, QTextCursor)
+from qt.core import QEvent, QPainter, QPalette, QSize, QStaticText, Qt, QTextCursor, QTextOption, QTimer, QWidget
 
-from calibre import prints, prepare_string_for_xml
+from calibre import prepare_string_for_xml, prints
 from calibre.gui2 import error_dialog
 from calibre.gui2.tweak_book.widgets import make_highlighted_text
 from calibre.utils.icu import string_length
diff --git a/src/calibre/gui2/tweak_book/diff/highlight.py b/src/calibre/gui2/tweak_book/diff/highlight.py
index 07c6a757b9..115a142212 100644
--- a/src/calibre/gui2/tweak_book/diff/highlight.py
+++ b/src/calibre/gui2/tweak_book/diff/highlight.py
@@ -6,12 +6,13 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 
-from qt.core import QTextDocument, QTextCursor, QPlainTextDocumentLayout
+from qt.core import QPlainTextDocumentLayout, QTextCursor, QTextDocument
 
 from calibre.gui2.tweak_book import tprefs
-from calibre.gui2.tweak_book.editor.text import get_highlighter as calibre_highlighter, SyntaxHighlighter
+from calibre.gui2.tweak_book.editor.syntax.utils import NULL_FMT, format_for_pygments_token
+from calibre.gui2.tweak_book.editor.text import SyntaxHighlighter
+from calibre.gui2.tweak_book.editor.text import get_highlighter as calibre_highlighter
 from calibre.gui2.tweak_book.editor.themes import get_theme, highlight_to_char_format
-from calibre.gui2.tweak_book.editor.syntax.utils import format_for_pygments_token, NULL_FMT
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/gui2/tweak_book/diff/main.py b/src/calibre/gui2/tweak_book/diff/main.py
index 6e303767f2..bb6b48e54d 100644
--- a/src/calibre/gui2/tweak_book/diff/main.py
+++ b/src/calibre/gui2/tweak_book/diff/main.py
@@ -9,10 +9,29 @@ import re
 import sys
 import textwrap
 from functools import partial
+
 from qt.core import (
-    QApplication, QCursor, QDialogButtonBox, QEventLoop, QGridLayout, QHBoxLayout,
-    QIcon, QKeySequence, QLabel, QMenu, QPainter, QRadioButton, QRect, QSize,
-    QStackedLayout, Qt, QTimer, QToolButton, QVBoxLayout, QWidget, pyqtSignal,
+    QApplication,
+    QCursor,
+    QDialogButtonBox,
+    QEventLoop,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QMenu,
+    QPainter,
+    QRadioButton,
+    QRect,
+    QSize,
+    QStackedLayout,
+    Qt,
+    QTimer,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.ebooks.oeb.polish.container import Container
diff --git a/src/calibre/gui2/tweak_book/diff/view.py b/src/calibre/gui2/tweak_book/diff/view.py
index 3b023420ed..519b9a3f41 100644
--- a/src/calibre/gui2/tweak_book/diff/view.py
+++ b/src/calibre/gui2/tweak_book/diff/view.py
@@ -2,18 +2,43 @@
 # License: GPLv3 Copyright: 2014, Kovid Goyal <kovid at kovidgoyal.net>
 
 import re
-import regex
 import unicodedata
 from collections import OrderedDict, namedtuple
 from difflib import SequenceMatcher
 from functools import partial
 from itertools import chain
 from math import ceil
+
+import regex
 from qt.core import (
-    QApplication, QBrush, QColor, QEvent, QEventLoop, QFont, QHBoxLayout, QIcon, QImage,
-    QKeySequence, QMenu, QPainter, QPainterPath, QPalette, QPen, QPixmap,
-    QPlainTextEdit, QRect, QScrollBar, QSplitter, QSplitterHandle, Qt, QTextCharFormat,
-    QTextCursor, QTextLayout, QTimer, QWidget, pyqtSignal,
+    QApplication,
+    QBrush,
+    QColor,
+    QEvent,
+    QEventLoop,
+    QFont,
+    QHBoxLayout,
+    QIcon,
+    QImage,
+    QKeySequence,
+    QMenu,
+    QPainter,
+    QPainterPath,
+    QPalette,
+    QPen,
+    QPixmap,
+    QPlainTextEdit,
+    QRect,
+    QScrollBar,
+    QSplitter,
+    QSplitterHandle,
+    Qt,
+    QTextCharFormat,
+    QTextCursor,
+    QTextLayout,
+    QTimer,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import fit_image, human_readable
@@ -21,9 +46,7 @@ from calibre.gui2 import info_dialog
 from calibre.gui2.tweak_book import tprefs
 from calibre.gui2.tweak_book.diff import get_sequence_matcher
 from calibre.gui2.tweak_book.diff.highlight import get_highlighter
-from calibre.gui2.tweak_book.editor.text import (
-    LineNumbers, PlainTextEdit, default_font_family,
-)
+from calibre.gui2.tweak_book.editor.text import LineNumbers, PlainTextEdit, default_font_family
 from calibre.gui2.tweak_book.editor.themes import get_theme, theme_color
 from calibre.gui2.widgets import BusyCursor
 from calibre.startup import connect_lambda
@@ -48,6 +71,7 @@ def beautify_text(raw, syntax):
         pretty_xml_tree(root)
     elif syntax == 'css':
         import logging
+
         from css_parser import CSSParser, log
 
         from calibre.ebooks.oeb.base import _css_logger, serialize
diff --git a/src/calibre/gui2/tweak_book/download.py b/src/calibre/gui2/tweak_book/download.py
index 97b09b84df..6952462dc8 100644
--- a/src/calibre/gui2/tweak_book/download.py
+++ b/src/calibre/gui2/tweak_book/download.py
@@ -2,15 +2,25 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import (
-    QDialogButtonBox, QGridLayout, QIcon, QLabel, QListWidget, QListWidgetItem,
-    QProgressBar, QScrollArea, QSize, Qt, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 
-from calibre.ebooks.oeb.polish.download import (
-    download_external_resources, get_external_resources, replace_resources,
+from qt.core import (
+    QDialogButtonBox,
+    QGridLayout,
+    QIcon,
+    QLabel,
+    QListWidget,
+    QListWidgetItem,
+    QProgressBar,
+    QScrollArea,
+    QSize,
+    Qt,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
+
+from calibre.ebooks.oeb.polish.download import download_external_resources, get_external_resources, replace_resources
 from calibre.gui2 import error_dialog, info_dialog, warning_dialog
 from calibre.gui2.progress_indicator import WaitStack
 from calibre.gui2.tweak_book import current_container
diff --git a/src/calibre/gui2/tweak_book/editor/canvas.py b/src/calibre/gui2/tweak_book/editor/canvas.py
index 61a337625f..97165a7be4 100644
--- a/src/calibre/gui2/tweak_book/editor/canvas.py
+++ b/src/calibre/gui2/tweak_book/editor/canvas.py
@@ -8,20 +8,39 @@ import sys
 import weakref
 from functools import wraps
 from io import BytesIO
+
 from qt.core import (
-    QApplication, QColor, QIcon, QImage, QImageWriter, QPainter, QPen, QPixmap, QPointF,
-    QRect, QRectF, Qt, QTransform, QUndoCommand, QUndoStack, QWidget, pyqtSignal,
+    QApplication,
+    QColor,
+    QIcon,
+    QImage,
+    QImageWriter,
+    QPainter,
+    QPen,
+    QPixmap,
+    QPointF,
+    QRect,
+    QRectF,
+    Qt,
+    QTransform,
+    QUndoCommand,
+    QUndoStack,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import fit_image
 from calibre.gui2 import error_dialog, pixmap_to_data
-from calibre.gui2.dnd import (
-    DownloadDialog, dnd_get_image, dnd_has_extension, dnd_has_image, image_extensions,
-)
+from calibre.gui2.dnd import DownloadDialog, dnd_get_image, dnd_has_extension, dnd_has_image, image_extensions
 from calibre.gui2.tweak_book import capitalize
 from calibre.utils.img import (
-    despeckle_image, gaussian_blur_image, gaussian_sharpen_image, image_to_data,
-    normalize_image, oil_paint_image, remove_borders_from_image,
+    despeckle_image,
+    gaussian_blur_image,
+    gaussian_sharpen_image,
+    image_to_data,
+    normalize_image,
+    oil_paint_image,
+    remove_borders_from_image,
 )
 from calibre.utils.imghdr import identify
 
diff --git a/src/calibre/gui2/tweak_book/editor/image.py b/src/calibre/gui2/tweak_book/editor/image.py
index 715ac47963..2b821ea84c 100644
--- a/src/calibre/gui2/tweak_book/editor/image.py
+++ b/src/calibre/gui2/tweak_book/editor/image.py
@@ -5,9 +5,22 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
+
 from qt.core import (
-    QApplication, QCheckBox, QDialog, QDialogButtonBox, QFormLayout, QIcon,
-    QInputDialog, QLabel, QMainWindow, QMenu, QSize, QSpinBox, Qt, QToolButton,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QIcon,
+    QInputDialog,
+    QLabel,
+    QMainWindow,
+    QMenu,
+    QSize,
+    QSpinBox,
+    Qt,
+    QToolButton,
     pyqtSignal,
 )
 
diff --git a/src/calibre/gui2/tweak_book/editor/insert_resource.py b/src/calibre/gui2/tweak_book/editor/insert_resource.py
index d4ced61597..72503e614d 100644
--- a/src/calibre/gui2/tweak_book/editor/insert_resource.py
+++ b/src/calibre/gui2/tweak_book/editor/insert_resource.py
@@ -7,12 +7,36 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import os
 import sys
 from functools import partial
+
 from qt.core import (
-    QAbstractListModel, QApplication, QCheckBox, QClipboard, QDialog, QDialogButtonBox,
-    QFormLayout, QGridLayout, QHBoxLayout, QIcon, QInputDialog, QLabel, QLineEdit,
-    QListView, QMenu, QPainter, QPixmap, QRect, QSize, QSizePolicy,
-    QSortFilterProxyModel, QStyledItemDelegate, Qt, QToolButton, QTreeWidget,
-    QTreeWidgetItem, QVBoxLayout, pyqtSignal,
+    QAbstractListModel,
+    QApplication,
+    QCheckBox,
+    QClipboard,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QMenu,
+    QPainter,
+    QPixmap,
+    QRect,
+    QSize,
+    QSizePolicy,
+    QSortFilterProxyModel,
+    QStyledItemDelegate,
+    Qt,
+    QToolButton,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    pyqtSignal,
 )
 
 from calibre import fit_image
diff --git a/src/calibre/gui2/tweak_book/editor/smarts/css.py b/src/calibre/gui2/tweak_book/editor/smarts/css.py
index 0348ff4255..5f784d9aa5 100644
--- a/src/calibre/gui2/tweak_book/editor/smarts/css.py
+++ b/src/calibre/gui2/tweak_book/editor/smarts/css.py
@@ -11,8 +11,14 @@ from qt.core import Qt, QTextCursor
 from calibre.gui2.tweak_book import current_container
 from calibre.gui2.tweak_book.editor.smarts import NullSmarts
 from calibre.gui2.tweak_book.editor.smarts.utils import (
-    no_modifiers, get_leading_whitespace_on_block, get_text_before_cursor,
-    smart_home, smart_backspace, smart_tab, expand_tabs)
+    expand_tabs,
+    get_leading_whitespace_on_block,
+    get_text_before_cursor,
+    no_modifiers,
+    smart_backspace,
+    smart_home,
+    smart_tab,
+)
 
 
 def find_rule(raw, rule_address):
diff --git a/src/calibre/gui2/tweak_book/editor/smarts/html.py b/src/calibre/gui2/tweak_book/editor/smarts/html.py
index b83bdaf94f..c6b2e6e754 100644
--- a/src/calibre/gui2/tweak_book/editor/smarts/html.py
+++ b/src/calibre/gui2/tweak_book/editor/smarts/html.py
@@ -7,9 +7,10 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import re
 import sys
 from contextlib import contextmanager
-from css_parser import parseStyle
 from itertools import chain
 from operator import itemgetter
+
+from css_parser import parseStyle
 from qt.core import Qt, QTextCursor, QTextEdit
 
 from calibre import prepare_string_for_xml, xml_entity_to_unicode
@@ -20,12 +21,16 @@ from calibre.gui2 import error_dialog
 from calibre.gui2.tweak_book import current_container, tprefs
 from calibre.gui2.tweak_book.editor.smarts import NullSmarts
 from calibre.gui2.tweak_book.editor.smarts.utils import (
-    expand_tabs, get_leading_whitespace_on_block, get_text_after_cursor,
-    get_text_before_cursor, no_modifiers, smart_backspace, smart_home, smart_tab
-)
-from calibre.gui2.tweak_book.editor.syntax.html import (
-    ATTR_END, ATTR_NAME, ATTR_START, ATTR_VALUE
+    expand_tabs,
+    get_leading_whitespace_on_block,
+    get_text_after_cursor,
+    get_text_before_cursor,
+    no_modifiers,
+    smart_backspace,
+    smart_home,
+    smart_tab,
 )
+from calibre.gui2.tweak_book.editor.syntax.html import ATTR_END, ATTR_NAME, ATTR_START, ATTR_VALUE
 from calibre.utils.icu import utf16_length
 
 get_offset = itemgetter(0)
diff --git a/src/calibre/gui2/tweak_book/editor/smarts/python.py b/src/calibre/gui2/tweak_book/editor/smarts/python.py
index 4a4fcd3770..b768a4a669 100644
--- a/src/calibre/gui2/tweak_book/editor/smarts/python.py
+++ b/src/calibre/gui2/tweak_book/editor/smarts/python.py
@@ -9,9 +9,9 @@ import re
 from qt.core import Qt
 
 from calibre.gui2.tweak_book.editor.smarts import NullSmarts
-from calibre.gui2.tweak_book.editor.smarts.utils import (
-    get_text_before_cursor, get_leading_whitespace_on_block as lw,
-    smart_home, smart_backspace, smart_tab)
+from calibre.gui2.tweak_book.editor.smarts.utils import get_leading_whitespace_on_block as lw
+from calibre.gui2.tweak_book.editor.smarts.utils import get_text_before_cursor, smart_backspace, smart_home, smart_tab
+
 
 def get_leading_whitespace_on_block(editor, previous=False):
     return expand_tabs(lw(editor, previous=previous))
@@ -74,5 +74,6 @@ class Smarts(NullSmarts):
 
 if __name__ == '__main__':
     import os
+
     from calibre.gui2.tweak_book.editor.widget import launch_editor
     launch_editor(os.path.abspath(__file__), syntax='python')
diff --git a/src/calibre/gui2/tweak_book/editor/snippets.py b/src/calibre/gui2/tweak_book/editor/snippets.py
index 80490f3f6c..c598e2829b 100644
--- a/src/calibre/gui2/tweak_book/editor/snippets.py
+++ b/src/calibre/gui2/tweak_book/editor/snippets.py
@@ -10,10 +10,28 @@ import weakref
 from collections import OrderedDict, namedtuple
 from itertools import groupby
 from operator import attrgetter, itemgetter
+
 from qt.core import (
-    QDialog, QDialogButtonBox, QFrame, QGridLayout, QHBoxLayout, QIcon, QLabel,
-    QLineEdit, QListView, QListWidget, QListWidgetItem, QObject, QPushButton, QSize,
-    QStackedLayout, Qt, QTextCursor, QToolButton, QVBoxLayout, QWidget
+    QDialog,
+    QDialogButtonBox,
+    QFrame,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QListWidget,
+    QListWidgetItem,
+    QObject,
+    QPushButton,
+    QSize,
+    QStackedLayout,
+    Qt,
+    QTextCursor,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
 )
 
 from calibre.constants import ismacos
@@ -26,6 +44,7 @@ from calibre.utils.icu import string_length as strlen
 from calibre.utils.localization import localize_user_manual_link
 from polyglot.builtins import codepoint_to_chr, iteritems, itervalues
 
+
 def string_length(x):
     return strlen(str(x))  # Needed on narrow python builds, as subclasses of unicode dont work
 KEY = Qt.Key.Key_J
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/base.py b/src/calibre/gui2/tweak_book/editor/syntax/base.py
index 6d5893cceb..d47b7e39a1 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/base.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/base.py
@@ -4,9 +4,8 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from collections import defaultdict, deque
-from qt.core import (
-    QTextBlock, QTextBlockUserData, QTextCursor, QTextFormat, QTextLayout, QTimer,
-)
+
+from qt.core import QTextBlock, QTextBlockUserData, QTextCursor, QTextFormat, QTextLayout, QTimer
 
 from calibre.gui2.widgets import BusyCursor
 from calibre.utils.icu import utf16_length
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/css.py b/src/calibre/gui2/tweak_book/editor/syntax/css.py
index d90c4145d3..1efd037ac2 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/css.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/css.py
@@ -9,7 +9,7 @@ import re
 from qt.core import QTextBlockUserData
 
 from calibre.gui2.tweak_book import verify_link
-from calibre.gui2.tweak_book.editor import syntax_text_char_format, LINK_PROPERTY, CSS_PROPERTY
+from calibre.gui2.tweak_book.editor import CSS_PROPERTY, LINK_PROPERTY, syntax_text_char_format
 from calibre.gui2.tweak_book.editor.syntax.base import SyntaxHighlighter
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/html.py b/src/calibre/gui2/tweak_book/editor/syntax/html.py
index ec346bdbbf..9ac523474c 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/html.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/html.py
@@ -7,19 +7,24 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import re
 from collections import namedtuple
 from functools import partial
+
 from qt.core import QFont, QTextBlockUserData, QTextCharFormat, QVariant
 
 from calibre.ebooks.oeb.polish.spell import html_spell_tags, patterns, xml_spell_tags
 from calibre.gui2.tweak_book import dictionaries, tprefs, verify_link
 from calibre.gui2.tweak_book.editor import (
-    CLASS_ATTRIBUTE_PROPERTY, LINK_PROPERTY, SPELL_LOCALE_PROPERTY, SPELL_PROPERTY,
-    TAG_NAME_PROPERTY, store_locale, syntax_text_char_format
+    CLASS_ATTRIBUTE_PROPERTY,
+    LINK_PROPERTY,
+    SPELL_LOCALE_PROPERTY,
+    SPELL_PROPERTY,
+    TAG_NAME_PROPERTY,
+    store_locale,
+    syntax_text_char_format,
 )
 from calibre.gui2.tweak_book.editor.syntax.base import SyntaxHighlighter, run_loop
-from calibre.gui2.tweak_book.editor.syntax.css import (
-    CSSState, CSSUserData, create_formats as create_css_formats,
-    state_map as css_state_map
-)
+from calibre.gui2.tweak_book.editor.syntax.css import CSSState, CSSUserData
+from calibre.gui2.tweak_book.editor.syntax.css import create_formats as create_css_formats
+from calibre.gui2.tweak_book.editor.syntax.css import state_map as css_state_map
 from calibre.spell.break_iterator import split_into_words_and_positions
 from calibre.spell.dictionary import parse_lang_code
 from calibre_extensions import html_syntax_highlighter as _speedup
@@ -521,6 +526,7 @@ class XMLHighlighter(Highlighter):
 
 def profile():
     import sys
+
     from qt.core import QTextDocument
 
     from calibre.gui2 import Application
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/javascript.py b/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
index 2eb9a7c712..3ed167f5fe 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/javascript.py
@@ -4,16 +4,13 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import pygments.unistring as uni
 import re
-from pygments.lexer import RegexLexer, default, include
-from pygments.token import (
-    Comment, Keyword, Name, Number, Operator, Punctuation, String, Text,
-)
 
-from calibre.gui2.tweak_book.editor.syntax.pygments_highlighter import (
-    create_highlighter,
-)
+import pygments.unistring as uni
+from pygments.lexer import RegexLexer, default, include
+from pygments.token import Comment, Keyword, Name, Number, Operator, Punctuation, String, Text
+
+from calibre.gui2.tweak_book.editor.syntax.pygments_highlighter import create_highlighter
 from calibre.utils.resources import get_path as P
 from polyglot.builtins import native_string_type
 
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py b/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py
index 0c916fa823..7297730750 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/pygments_highlighter.py
@@ -7,11 +7,11 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import numbers
 from functools import partial
 
+from pygments.lexer import Error, _TokenType
 from qt.core import QTextBlockUserData
-from pygments.lexer import _TokenType, Error
 
 from calibre.gui2.tweak_book.editor.syntax.base import SyntaxHighlighter
-from calibre.gui2.tweak_book.editor.syntax.utils import format_for_pygments_token, NULL_FMT
+from calibre.gui2.tweak_book.editor.syntax.utils import NULL_FMT, format_for_pygments_token
 
 NORMAL = 0
 
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/python.py b/src/calibre/gui2/tweak_book/editor/syntax/python.py
index 8af7d286e6..50537b7c13 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/python.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/python.py
@@ -12,5 +12,6 @@ Highlighter = create_highlighter('PythonHighlighter', PythonLexer)
 
 if __name__ == '__main__':
     import os
+
     from calibre.gui2.tweak_book.editor.widget import launch_editor
     launch_editor(os.path.abspath(__file__), syntax='python')
diff --git a/src/calibre/gui2/tweak_book/editor/text.py b/src/calibre/gui2/tweak_book/editor/text.py
index 3fb2c1da44..f81d7958b1 100644
--- a/src/calibre/gui2/tweak_book/editor/text.py
+++ b/src/calibre/gui2/tweak_book/editor/text.py
@@ -5,38 +5,45 @@
 import importlib
 import os
 import re
-import regex
 import textwrap
 import unicodedata
+
+import regex
 from qt.core import (
-    QColor, QColorDialog, QFont, QFontDatabase, QKeySequence, QPainter, QPalette,
-    QPlainTextEdit, QRect, QSize, Qt, QTextCursor, QTextEdit, QTextFormat, QTimer,
-    QToolTip, QWidget, pyqtSignal
+    QColor,
+    QColorDialog,
+    QFont,
+    QFontDatabase,
+    QKeySequence,
+    QPainter,
+    QPalette,
+    QPlainTextEdit,
+    QRect,
+    QSize,
+    Qt,
+    QTextCursor,
+    QTextEdit,
+    QTextFormat,
+    QTimer,
+    QToolTip,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import prepare_string_for_xml
 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, css_text
 from calibre.ebooks.oeb.polish.replace import get_recommended_folders
 from calibre.ebooks.oeb.polish.utils import guess_type
-from calibre.gui2.tweak_book import (
-    CONTAINER_DND_MIMETYPE, TOP, current_container, tprefs
-)
+from calibre.gui2.tweak_book import CONTAINER_DND_MIMETYPE, TOP, current_container, tprefs
 from calibre.gui2.tweak_book.completion.popup import CompletionPopup
-from calibre.gui2.tweak_book.editor import (
-    CLASS_ATTRIBUTE_PROPERTY, LINK_PROPERTY, SPELL_LOCALE_PROPERTY, SPELL_PROPERTY,
-    SYNTAX_PROPERTY, store_locale
-)
+from calibre.gui2.tweak_book.editor import CLASS_ATTRIBUTE_PROPERTY, LINK_PROPERTY, SPELL_LOCALE_PROPERTY, SPELL_PROPERTY, SYNTAX_PROPERTY, store_locale
 from calibre.gui2.tweak_book.editor.smarts import NullSmarts
 from calibre.gui2.tweak_book.editor.snippets import SnippetManager
 from calibre.gui2.tweak_book.editor.syntax.base import SyntaxHighlighter
-from calibre.gui2.tweak_book.editor.themes import (
-    get_theme, theme_color, theme_format
-)
+from calibre.gui2.tweak_book.editor.themes import get_theme, theme_color, theme_format
 from calibre.gui2.tweak_book.widgets import PARAGRAPH_SEPARATOR, PlainTextEdit
 from calibre.spell.break_iterator import index_of
-from calibre.utils.icu import (
-    capitalize, lower, safe_chr, string_length, swapcase, upper, utf16_length
-)
+from calibre.utils.icu import capitalize, lower, safe_chr, string_length, swapcase, upper, utf16_length
 from calibre.utils.img import image_to_data
 from calibre.utils.titlecase import titlecase
 from polyglot.builtins import as_unicode
diff --git a/src/calibre/gui2/tweak_book/editor/themes.py b/src/calibre/gui2/tweak_book/editor/themes.py
index b69ca83c28..a1a3f0b35f 100644
--- a/src/calibre/gui2/tweak_book/editor/themes.py
+++ b/src/calibre/gui2/tweak_book/editor/themes.py
@@ -7,10 +7,33 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 from collections import namedtuple
 
 from qt.core import (
-    QColor, QBrush, QFont, QApplication, QPalette, QComboBox,
-    QPushButton, QIcon, QFormLayout, QLineEdit, QWidget, QScrollArea,
-    QVBoxLayout, Qt, QHBoxLayout, pyqtSignal, QPixmap, QColorDialog, QDialog,
-    QToolButton, QCheckBox, QSize, QLabel, QSplitter, QTextCharFormat, QDialogButtonBox)
+    QApplication,
+    QBrush,
+    QCheckBox,
+    QColor,
+    QColorDialog,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFormLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QPalette,
+    QPixmap,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSplitter,
+    Qt,
+    QTextCharFormat,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.tweak_book import tprefs
diff --git a/src/calibre/gui2/tweak_book/editor/widget.py b/src/calibre/gui2/tweak_book/editor/widget.py
index 6b2a1bc8e7..759da1874d 100644
--- a/src/calibre/gui2/tweak_book/editor/widget.py
+++ b/src/calibre/gui2/tweak_book/editor/widget.py
@@ -7,27 +7,35 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import math
 import unicodedata
 from functools import partial
+
 from qt.core import (
-    QAction, QApplication, QColor, QIcon, QImage, QInputDialog, QMainWindow, QMenu,
-    QPainter, QPixmap, QSize, Qt, QTextCursor, QToolButton, pyqtSignal,
-    qDrawShadeRect
+    QAction,
+    QApplication,
+    QColor,
+    QIcon,
+    QImage,
+    QInputDialog,
+    QMainWindow,
+    QMenu,
+    QPainter,
+    QPixmap,
+    QSize,
+    Qt,
+    QTextCursor,
+    QToolButton,
+    pyqtSignal,
+    qDrawShadeRect,
 )
 
 from calibre import prints
 from calibre.constants import DEBUG
 from calibre.ebooks.chardet import replace_encoding_declarations
 from calibre.gui2 import error_dialog, open_url
-from calibre.gui2.tweak_book import (
-    actions, current_container, dictionaries, editor_name, editor_toolbar_actions,
-    editors, tprefs, update_mark_text_action
-)
-from calibre.gui2.tweak_book.editor import (
-    CLASS_ATTRIBUTE_PROPERTY, CSS_PROPERTY, LINK_PROPERTY, SPELL_PROPERTY,
-    TAG_NAME_PROPERTY
-)
+from calibre.gui2.tweak_book import actions, current_container, dictionaries, editor_name, editor_toolbar_actions, editors, tprefs, update_mark_text_action
+from calibre.gui2.tweak_book.editor import CLASS_ATTRIBUTE_PROPERTY, CSS_PROPERTY, LINK_PROPERTY, SPELL_PROPERTY, TAG_NAME_PROPERTY
 from calibre.gui2.tweak_book.editor.help import help_url
 from calibre.gui2.tweak_book.editor.text import TextEdit
-from calibre.utils.icu import utf16_length, primary_sort_key
+from calibre.utils.icu import primary_sort_key, utf16_length
 from polyglot.builtins import itervalues, string_or_bytes
 
 
@@ -513,9 +521,7 @@ class Editor(QMainWindow):
         return False
 
     def pretty_print(self, name):
-        from calibre.ebooks.oeb.polish.pretty import (
-            pretty_css, pretty_html, pretty_xml
-        )
+        from calibre.ebooks.oeb.polish.pretty import pretty_css, pretty_html, pretty_xml
         if self.syntax in {'css', 'html', 'xml'}:
             func = {'css':pretty_css, 'xml':pretty_xml}.get(self.syntax, pretty_html)
             original_text = str(self.editor.toPlainText())
diff --git a/src/calibre/gui2/tweak_book/file_list.py b/src/calibre/gui2/tweak_book/file_list.py
index 0e9d454b21..5fae580bc6 100644
--- a/src/calibre/gui2/tweak_book/file_list.py
+++ b/src/calibre/gui2/tweak_book/file_list.py
@@ -8,31 +8,51 @@ import sys
 import textwrap
 from collections import Counter, OrderedDict, defaultdict
 from functools import lru_cache, partial
+
 from qt.core import (
-    QAbstractItemView, QApplication, QCheckBox, QDialog, QDialogButtonBox, QFont,
-    QFormLayout, QGridLayout, QIcon, QInputDialog, QItemSelectionModel, QLabel,
-    QLineEdit, QListWidget, QListWidgetItem, QMenu, QPainter, QPixmap, QRadioButton,
-    QScrollArea, QSize, QSpinBox, QStyle, QStyledItemDelegate, Qt, QTimer, QTreeView,
-    QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal, sip,
+    QAbstractItemView,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFormLayout,
+    QGridLayout,
+    QIcon,
+    QInputDialog,
+    QItemSelectionModel,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QPainter,
+    QPixmap,
+    QRadioButton,
+    QScrollArea,
+    QSize,
+    QSpinBox,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTimer,
+    QTreeView,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+    sip,
 )
 
 from calibre import human_readable, sanitize_file_name
 from calibre.ebooks.oeb.base import OEB_DOCS, OEB_STYLES
-from calibre.ebooks.oeb.polish.cover import (
-    get_cover_page_name, get_raster_cover_name, is_raster_image,
-)
+from calibre.ebooks.oeb.polish.cover import get_cover_page_name, get_raster_cover_name, is_raster_image
 from calibre.ebooks.oeb.polish.css import add_stylesheet_links
-from calibre.ebooks.oeb.polish.replace import (
-    get_recommended_folders, get_spine_order_for_all_files,
-)
+from calibre.ebooks.oeb.polish.replace import get_recommended_folders, get_spine_order_for_all_files
 from calibre.ebooks.oeb.polish.utils import OEB_FONTS, guess_type
-from calibre.gui2 import (
-    choose_dir, choose_files, choose_save_file, elided_text, error_dialog,
-    make_view_use_window_background, question_dialog,
-)
-from calibre.gui2.tweak_book import (
-    CONTAINER_DND_MIMETYPE, current_container, editors, tprefs,
-)
+from calibre.gui2 import choose_dir, choose_files, choose_save_file, elided_text, error_dialog, make_view_use_window_background, question_dialog
+from calibre.gui2.tweak_book import CONTAINER_DND_MIMETYPE, current_container, editors, tprefs
 from calibre.gui2.tweak_book.editor import syntax_from_mime
 from calibre.gui2.tweak_book.templates import template_for
 from calibre.startup import connect_lambda
diff --git a/src/calibre/gui2/tweak_book/function_replace.py b/src/calibre/gui2/tweak_book/function_replace.py
index 9b34f576ff..2bdfff212d 100644
--- a/src/calibre/gui2/tweak_book/function_replace.py
+++ b/src/calibre/gui2/tweak_book/function_replace.py
@@ -8,14 +8,10 @@ import io
 import re
 import sys
 import weakref
-from qt.core import (
-    QApplication, QDialogButtonBox, QFontMetrics, QHBoxLayout, QIcon, QLabel,
-    QPlainTextEdit, QSize, Qt, QVBoxLayout, pyqtSignal,
-)
 
-from calibre.ebooks.oeb.polish.utils import (
-    apply_func_to_html_text, apply_func_to_match_groups,
-)
+from qt.core import QApplication, QDialogButtonBox, QFontMetrics, QHBoxLayout, QIcon, QLabel, QPlainTextEdit, QSize, Qt, QVBoxLayout, pyqtSignal
+
+from calibre.ebooks.oeb.polish.utils import apply_func_to_html_text, apply_func_to_match_groups
 from calibre.gui2 import error_dialog
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.gui2.tweak_book import dictionaries
diff --git a/src/calibre/gui2/tweak_book/job.py b/src/calibre/gui2/tweak_book/job.py
index dd39b40c7f..b7c32b0da7 100644
--- a/src/calibre/gui2/tweak_book/job.py
+++ b/src/calibre/gui2/tweak_book/job.py
@@ -5,10 +5,10 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import time
-from threading import Thread
 from functools import partial
+from threading import Thread
 
-from qt.core import (QWidget, QVBoxLayout, QLabel, Qt, QPainter, QBrush, QRect, QApplication, QCursor)
+from qt.core import QApplication, QBrush, QCursor, QLabel, QPainter, QRect, Qt, QVBoxLayout, QWidget
 
 from calibre.gui2 import Dispatcher
 from calibre.gui2.progress_indicator import ProgressIndicator
diff --git a/src/calibre/gui2/tweak_book/jump_to_class.py b/src/calibre/gui2/tweak_book/jump_to_class.py
index 2b0d6ba599..7c9867f50a 100644
--- a/src/calibre/gui2/tweak_book/jump_to_class.py
+++ b/src/calibre/gui2/tweak_book/jump_to_class.py
@@ -2,13 +2,14 @@
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 from contextlib import suppress
-from css_parser.css import CSSRule
 from typing import List, NamedTuple, Optional, Tuple
 
+from css_parser.css import CSSRule
+from css_selectors import Select, SelectorError
+
 from calibre.ebooks.oeb.parse_utils import barename
 from calibre.ebooks.oeb.polish.container import get_container
 from calibre.ebooks.oeb.polish.parsing import parse
-from css_selectors import Select, SelectorError
 
 
 class NoMatchingTagFound(KeyError):
diff --git a/src/calibre/gui2/tweak_book/live_css.py b/src/calibre/gui2/tweak_book/live_css.py
index bf665efa78..9b102444ca 100644
--- a/src/calibre/gui2/tweak_book/live_css.py
+++ b/src/calibre/gui2/tweak_book/live_css.py
@@ -5,17 +5,33 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
+
+from css_selectors import SelectorError, parse
 from qt.core import (
-    QWidget, QTimer, QStackedLayout, QLabel, QScrollArea, QVBoxLayout,
-    QPainter, Qt, QPalette, QRect, QSize, QSizePolicy, pyqtSignal,
-    QColor, QMenu, QApplication, QIcon, QUrl)
+    QApplication,
+    QColor,
+    QIcon,
+    QLabel,
+    QMenu,
+    QPainter,
+    QPalette,
+    QRect,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QStackedLayout,
+    Qt,
+    QTimer,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
 
 from calibre.constants import FAKE_HOST, FAKE_PROTOCOL
-from calibre.gui2.tweak_book import editors, actions, tprefs
-from calibre.gui2.tweak_book.editor.themes import get_theme, theme_color
+from calibre.gui2.tweak_book import actions, editors, tprefs
 from calibre.gui2.tweak_book.editor.text import default_font_family
-from css_selectors import parse, SelectorError
-
+from calibre.gui2.tweak_book.editor.themes import get_theme, theme_color
 
 lowest_specificity = (-sys.maxsize, 0, 0, 0, 0, 0)
 
diff --git a/src/calibre/gui2/tweak_book/main.py b/src/calibre/gui2/tweak_book/main.py
index b103949e73..b5056ccb24 100644
--- a/src/calibre/gui2/tweak_book/main.py
+++ b/src/calibre/gui2/tweak_book/main.py
@@ -10,9 +10,7 @@ from qt.core import QIcon
 
 from calibre.constants import EDITOR_APP_UID, islinux
 from calibre.ebooks.oeb.polish.check.css import shutdown as shutdown_css_check_pool
-from calibre.gui2 import (
-    Application, decouple, set_gui_prefs, setup_gui_option_parser
-)
+from calibre.gui2 import Application, decouple, set_gui_prefs, setup_gui_option_parser
 from calibre.ptempfile import reset_base_dir
 from calibre.utils.config import OptionParser
 
diff --git a/src/calibre/gui2/tweak_book/manage_fonts.py b/src/calibre/gui2/tweak_book/manage_fonts.py
index ed9ce2eeb8..e755c08d95 100644
--- a/src/calibre/gui2/tweak_book/manage_fonts.py
+++ b/src/calibre/gui2/tweak_book/manage_fonts.py
@@ -7,10 +7,29 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 import sys
 import textwrap
 from io import BytesIO
+
 from qt.core import (
-    QAbstractItemView, QAbstractTableModel, QApplication, QDialog, QDialogButtonBox,
-    QFormLayout, QHBoxLayout, QIcon, QLabel, QLineEdit, QMessageBox, QPushButton, QSize,
-    QSplitter, Qt, QTableView, QTextEdit, QTimer, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QAbstractTableModel,
+    QApplication,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QMessageBox,
+    QPushButton,
+    QSize,
+    QSplitter,
+    Qt,
+    QTableView,
+    QTextEdit,
+    QTimer,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.ebooks.oeb.polish.container import get_container
@@ -21,7 +40,8 @@ from calibre.gui2.tweak_book.widgets import Dialog
 from calibre.gui2.widgets import BusyCursor
 from calibre.utils.fonts.metadata import FontMetadata, UnsupportedFont
 from calibre.utils.fonts.scanner import NoFonts, font_scanner
-from calibre.utils.icu import lower as icu_lower, primary_sort_key as sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import primary_sort_key as sort_key
 from calibre.utils.localization import ngettext
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/gui2/tweak_book/plugin.py b/src/calibre/gui2/tweak_book/plugin.py
index e7a0990a29..4565d794ec 100644
--- a/src/calibre/gui2/tweak_book/plugin.py
+++ b/src/calibre/gui2/tweak_book/plugin.py
@@ -6,6 +6,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import importlib
 import sys
+
 from qt.core import QToolButton
 
 from calibre import prints
diff --git a/src/calibre/gui2/tweak_book/polish.py b/src/calibre/gui2/tweak_book/polish.py
index c4f8e0f200..a1abf6439c 100644
--- a/src/calibre/gui2/tweak_book/polish.py
+++ b/src/calibre/gui2/tweak_book/polish.py
@@ -5,14 +5,34 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
-from qt.core import (
-    QAbstractItemView, QApplication, QCheckBox, QDialog, QDialogButtonBox, QHBoxLayout,
-    QIcon, QLabel, QListWidget, QListWidgetItem, QPalette, QPen, QPixmap, QProgressBar,
-    QSize, QSpinBox, QStyle, QStyledItemDelegate, Qt, QTextBrowser, QVBoxLayout,
-    QWidget, pyqtSignal,
-)
 from threading import Thread
 
+from qt.core import (
+    QAbstractItemView,
+    QApplication,
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QListWidget,
+    QListWidgetItem,
+    QPalette,
+    QPen,
+    QPixmap,
+    QProgressBar,
+    QSize,
+    QSpinBox,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTextBrowser,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import fit_image, force_unicode, human_readable
 from calibre.ebooks.oeb.polish.main import CUSTOMIZATION
 from calibre.gui2 import empty_index, question_dialog
@@ -326,9 +346,10 @@ class CompressImagesProgress(Dialog):
 if __name__ == '__main__':
     from calibre.gui2 import Application
     app = Application([])
-    import sip
     import sys
 
+    import sip
+
     from calibre.ebooks.oeb.polish.container import get_container
     c = get_container(sys.argv[-1], tweak_mode=True)
     set_current_container(c)
diff --git a/src/calibre/gui2/tweak_book/preferences.py b/src/calibre/gui2/tweak_book/preferences.py
index 942fdc6f76..558a9d4e42 100644
--- a/src/calibre/gui2/tweak_book/preferences.py
+++ b/src/calibre/gui2/tweak_book/preferences.py
@@ -10,24 +10,46 @@ from copy import copy, deepcopy
 from functools import partial
 from itertools import product
 from operator import attrgetter, methodcaller
+
 from qt.core import (
-    QAbstractItemView, QCheckBox, QComboBox, QDialog, QDialogButtonBox, QDoubleSpinBox,
-    QFont, QFontComboBox, QFormLayout, QGridLayout, QGroupBox, QHBoxLayout, QIcon,
-    QLabel, QListView, QListWidget, QListWidgetItem, QPushButton, QRadioButton, QSize,
-    QSizePolicy, QSpacerItem, QSpinBox, QStackedWidget, Qt, QTimer, QToolButton,
-    QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QDoubleSpinBox,
+    QFont,
+    QFontComboBox,
+    QFormLayout,
+    QGridLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QListView,
+    QListWidget,
+    QListWidgetItem,
+    QPushButton,
+    QRadioButton,
+    QSize,
+    QSizePolicy,
+    QSpacerItem,
+    QSpinBox,
+    QStackedWidget,
+    Qt,
+    QTimer,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import prepare_string_for_xml
 from calibre.gui2 import info_dialog
 from calibre.gui2.font_family_chooser import FontFamilyChooser
 from calibre.gui2.keyboard import ShortcutConfig
-from calibre.gui2.tweak_book import (
-    actions, editor_toolbar_actions, toolbar_actions, tprefs,
-)
-from calibre.gui2.tweak_book.editor.themes import (
-    ThemeEditor, all_theme_names, default_theme,
-)
+from calibre.gui2.tweak_book import actions, editor_toolbar_actions, toolbar_actions, tprefs
+from calibre.gui2.tweak_book.editor.themes import ThemeEditor, all_theme_names, default_theme
 from calibre.gui2.tweak_book.spell import ManageDictionaries
 from calibre.gui2.tweak_book.widgets import Dialog
 from calibre.gui2.widgets2 import ColorButton
diff --git a/src/calibre/gui2/tweak_book/preview.py b/src/calibre/gui2/tweak_book/preview.py
index e46b09f279..1254b88cd4 100644
--- a/src/calibre/gui2/tweak_book/preview.py
+++ b/src/calibre/gui2/tweak_book/preview.py
@@ -6,28 +6,43 @@ import json
 import time
 from collections import defaultdict
 from functools import partial
+from threading import Thread
+
 from qt.core import (
-    QAction, QApplication, QByteArray, QHBoxLayout, QIcon, QLabel, QMenu, QSize,
-    QSizePolicy, QStackedLayout, Qt, QTimer, QToolBar, QUrl, QVBoxLayout, QWidget,
+    QAction,
+    QApplication,
+    QByteArray,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QMenu,
+    QSize,
+    QSizePolicy,
+    QStackedLayout,
+    Qt,
+    QTimer,
+    QToolBar,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
     pyqtSignal,
 )
 from qt.webengine import (
-    QWebEngineContextMenuRequest, QWebEnginePage, QWebEngineProfile, QWebEngineScript,
-    QWebEngineSettings, QWebEngineUrlRequestJob, QWebEngineUrlSchemeHandler,
+    QWebEngineContextMenuRequest,
+    QWebEnginePage,
+    QWebEngineProfile,
+    QWebEngineScript,
+    QWebEngineSettings,
+    QWebEngineUrlRequestJob,
+    QWebEngineUrlSchemeHandler,
     QWebEngineView,
 )
-from threading import Thread
 
 from calibre import prints
-from calibre.constants import (
-    FAKE_HOST, FAKE_PROTOCOL, __version__, is_running_from_develop, ismacos, iswindows,
-)
+from calibre.constants import FAKE_HOST, FAKE_PROTOCOL, __version__, is_running_from_develop, ismacos, iswindows
 from calibre.ebooks.oeb.base import OEB_DOCS, XHTML_MIME, serialize
 from calibre.ebooks.oeb.polish.parsing import parse
-from calibre.gui2 import (
-    NO_URL_FORMATTING, QT_HIDDEN_CLEAR_ACTION, error_dialog, is_dark_theme,
-    safe_open_url,
-)
+from calibre.gui2 import NO_URL_FORMATTING, QT_HIDDEN_CLEAR_ACTION, error_dialog, is_dark_theme, safe_open_url
 from calibre.gui2.palette import dark_color, dark_link_color, dark_text_color
 from calibre.gui2.tweak_book import TOP, actions, current_container, editors, tprefs
 from calibre.gui2.tweak_book.file_list import OpenWithHandler
@@ -36,10 +51,7 @@ from calibre.gui2.webengine import RestartingWebEngineView
 from calibre.gui2.widgets2 import HistoryLineEdit2
 from calibre.utils.ipc.simple_worker import offload_worker
 from calibre.utils.resources import get_path as P
-from calibre.utils.webengine import (
-    Bridge, create_script, from_js, insert_scripts, secure_webengine, setup_profile,
-    to_js,
-)
+from calibre.utils.webengine import Bridge, create_script, from_js, insert_scripts, secure_webengine, setup_profile, to_js
 from polyglot.builtins import iteritems
 from polyglot.queue import Empty, Queue
 from polyglot.urllib import urlparse
diff --git a/src/calibre/gui2/tweak_book/reports.py b/src/calibre/gui2/tweak_book/reports.py
index 74daaeaed8..d3cbbb9c6a 100644
--- a/src/calibre/gui2/tweak_book/reports.py
+++ b/src/calibre/gui2/tweak_book/reports.py
@@ -5,7 +5,6 @@ __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
-import regex
 import textwrap
 import time
 from collections import defaultdict
@@ -14,22 +13,52 @@ from csv import writer as csv_writer
 from functools import lru_cache, partial
 from io import StringIO
 from operator import itemgetter
-from qt.core import (
-    QAbstractItemModel, QAbstractItemView, QAbstractTableModel, QApplication,
-    QByteArray, QComboBox, QDialogButtonBox, QFont, QFontDatabase, QHBoxLayout,
-    QIcon, QLabel, QLineEdit, QListWidget, QListWidgetItem, QMenu, QModelIndex,
-    QPalette, QPixmap, QRadioButton, QRect, QSize, QSortFilterProxyModel, QSplitter,
-    QStackedLayout, QStackedWidget, QStyle, QStyledItemDelegate, Qt, QTableView,
-    QTextCursor, QTimer, QTreeView, QUrl, QVBoxLayout, QWidget, pyqtSignal
-)
 from threading import Thread
 
+import regex
+from qt.core import (
+    QAbstractItemModel,
+    QAbstractItemView,
+    QAbstractTableModel,
+    QApplication,
+    QByteArray,
+    QComboBox,
+    QDialogButtonBox,
+    QFont,
+    QFontDatabase,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QModelIndex,
+    QPalette,
+    QPixmap,
+    QRadioButton,
+    QRect,
+    QSize,
+    QSortFilterProxyModel,
+    QSplitter,
+    QStackedLayout,
+    QStackedWidget,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTableView,
+    QTextCursor,
+    QTimer,
+    QTreeView,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import fit_image, human_readable
 from calibre.constants import DEBUG
-from calibre.ebooks.oeb.polish.report import (
-    ClassElement, ClassEntry, ClassFileMatch, CSSEntry, CSSFileMatch, CSSRule,
-    LinkLocation, MatchLocation, gather_data
-)
+from calibre.ebooks.oeb.polish.report import ClassElement, ClassEntry, ClassFileMatch, CSSEntry, CSSFileMatch, CSSRule, LinkLocation, MatchLocation, gather_data
 from calibre.gui2 import choose_save_file, error_dialog, open_url, question_dialog
 from calibre.gui2.progress_indicator import ProgressIndicator
 from calibre.gui2.tweak_book import current_container, dictionaries, tprefs
diff --git a/src/calibre/gui2/tweak_book/save.py b/src/calibre/gui2/tweak_book/save.py
index 08f9567373..b631e7015d 100644
--- a/src/calibre/gui2/tweak_book/save.py
+++ b/src/calibre/gui2/tweak_book/save.py
@@ -4,17 +4,20 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import shutil, os, errno, stat
+import errno
+import os
+import shutil
+import stat
 from threading import Thread
 
-from qt.core import (QObject, pyqtSignal, QLabel, QWidget, QHBoxLayout, Qt, QSize)
+from qt.core import QHBoxLayout, QLabel, QObject, QSize, Qt, QWidget, pyqtSignal
 
 from calibre.constants import iswindows
-from calibre.ptempfile import PersistentTemporaryFile
 from calibre.gui2.progress_indicator import ProgressIndicator
+from calibre.ptempfile import PersistentTemporaryFile
 from calibre.utils import join_with_timeout
 from calibre.utils.filenames import atomic_rename, format_permissions
-from polyglot.queue import LifoQueue, Empty
+from polyglot.queue import Empty, LifoQueue
 
 
 def save_dir_container(container, path):
diff --git a/src/calibre/gui2/tweak_book/search.py b/src/calibre/gui2/tweak_book/search.py
index 80fd278c40..ff485b4429 100644
--- a/src/calibre/gui2/tweak_book/search.py
+++ b/src/calibre/gui2/tweak_book/search.py
@@ -3,35 +3,60 @@
 
 import copy
 import json
-import regex
 import time
 from collections import Counter, OrderedDict
 from functools import partial
+
+import regex
 from qt.core import (
-    QAbstractItemView, QAbstractListModel, QAction, QApplication, QCheckBox, QComboBox,
-    QDialog, QDialogButtonBox, QEvent, QFont, QFrame, QGridLayout, QHBoxLayout, QIcon,
-    QItemSelection, QItemSelectionModel, QKeySequence, QLabel, QLineEdit, QListView,
-    QMenu, QMimeData, QModelIndex, QPushButton, QScrollArea, QSize, QSizePolicy,
-    QStackedLayout, QStyledItemDelegate, Qt, QTimer, QToolBar, QToolButton, QVBoxLayout,
-    QWidget, pyqtSignal,
+    QAbstractItemView,
+    QAbstractListModel,
+    QAction,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QEvent,
+    QFont,
+    QFrame,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QItemSelection,
+    QItemSelectionModel,
+    QKeySequence,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QMenu,
+    QMimeData,
+    QModelIndex,
+    QPushButton,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QStackedLayout,
+    QStyledItemDelegate,
+    Qt,
+    QTimer,
+    QToolBar,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import prepare_string_for_xml
 from calibre.constants import iswindows
-from calibre.ebooks.conversion.search_replace import (
-    REGEX_FLAGS, compile_regular_expression,
-)
+from calibre.ebooks.conversion.search_replace import REGEX_FLAGS, compile_regular_expression
 from calibre.gui2 import choose_files, choose_save_file, error_dialog, info_dialog
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.dialogs.message_box import MessageBox
 from calibre.gui2.tweak_book import current_container, editors, tprefs
-from calibre.gui2.tweak_book.editor.snippets import (
-    KEY, MODIFIER, SnippetTextEdit, find_matching_snip, parse_template, string_length,
-)
-from calibre.gui2.tweak_book.function_replace import (
-    Function, FunctionBox, FunctionEditor, functions as replace_functions,
-    remove_function,
-)
+from calibre.gui2.tweak_book.editor.snippets import KEY, MODIFIER, SnippetTextEdit, find_matching_snip, parse_template, string_length
+from calibre.gui2.tweak_book.function_replace import Function, FunctionBox, FunctionEditor, remove_function
+from calibre.gui2.tweak_book.function_replace import functions as replace_functions
 from calibre.gui2.widgets import BusyCursor
 from calibre.gui2.widgets2 import FlowLayout, HistoryComboBox
 from calibre.startup import connect_lambda
diff --git a/src/calibre/gui2/tweak_book/spell.py b/src/calibre/gui2/tweak_book/spell.py
index 12fce21c2c..ffcc777bd2 100644
--- a/src/calibre/gui2/tweak_book/spell.py
+++ b/src/calibre/gui2/tweak_book/spell.py
@@ -9,44 +9,74 @@ import sys
 from collections import OrderedDict, defaultdict
 from functools import partial
 from itertools import chain
-from qt.core import (
-    QT_VERSION_STR, QAbstractItemView, QAbstractTableModel, QAction, QApplication,
-    QCheckBox, QComboBox, QDialog, QDialogButtonBox, QFont, QFormLayout, QGridLayout,
-    QHBoxLayout, QIcon, QInputDialog, QKeySequence, QLabel, QLineEdit, QListWidget,
-    QListWidgetItem, QMenu, QModelIndex, QPlainTextEdit, QPushButton, QSize,
-    QStackedLayout, Qt, QTableView, QTabWidget, QTimer, QToolButton, QTreeWidget,
-    QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 
+from qt.core import (
+    QT_VERSION_STR,
+    QAbstractItemView,
+    QAbstractTableModel,
+    QAction,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFormLayout,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QKeySequence,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QModelIndex,
+    QPlainTextEdit,
+    QPushButton,
+    QSize,
+    QStackedLayout,
+    Qt,
+    QTableView,
+    QTabWidget,
+    QTimer,
+    QToolButton,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre.constants import __appname__
 from calibre.ebooks.oeb.base import NCX_MIME, OEB_DOCS, OPF_MIME
-from calibre.ebooks.oeb.polish.spell import (
-    get_all_words, get_checkable_file_names, merge_locations, replace_word,
-    undo_replace_word,
-)
+from calibre.ebooks.oeb.polish.spell import get_all_words, get_checkable_file_names, merge_locations, replace_word, undo_replace_word
 from calibre.gui2 import choose_files, error_dialog
 from calibre.gui2.complete2 import LineEdit
 from calibre.gui2.languages import LanguagesEdit
 from calibre.gui2.progress_indicator import ProgressIndicator
-from calibre.gui2.tweak_book import (
-    current_container, dictionaries, editors, set_book_locale, tprefs,
-)
+from calibre.gui2.tweak_book import current_container, dictionaries, editors, set_book_locale, tprefs
 from calibre.gui2.tweak_book.widgets import Dialog
 from calibre.gui2.widgets import BusyCursor
 from calibre.gui2.widgets2 import FlowLayout
 from calibre.spell import DictionaryLocale
 from calibre.spell.break_iterator import split_into_words
 from calibre.spell.dictionary import (
-    best_locale_for_language, builtin_dictionaries, catalog_online_dictionaries,
-    custom_dictionaries, dprefs, get_dictionary, remove_dictionary, rename_dictionary,
+    best_locale_for_language,
+    builtin_dictionaries,
+    catalog_online_dictionaries,
+    custom_dictionaries,
+    dprefs,
+    get_dictionary,
+    remove_dictionary,
+    rename_dictionary,
 )
 from calibre.spell.import_from import import_from_online, import_from_oxt
 from calibre.startup import connect_lambda
 from calibre.utils.icu import contains, primary_contains, primary_sort_key, sort_key
-from calibre.utils.localization import (
-    calibre_langcode_to_name, canonicalize_lang, get_lang, get_language,
-)
+from calibre.utils.localization import calibre_langcode_to_name, canonicalize_lang, get_lang, get_language
 from calibre.utils.resources import get_path as P
 from calibre_extensions.progress_indicator import set_no_activate_on_click
 from polyglot.builtins import iteritems
diff --git a/src/calibre/gui2/tweak_book/text_search.py b/src/calibre/gui2/tweak_book/text_search.py
index aab65326a1..47df5d46c2 100644
--- a/src/calibre/gui2/tweak_book/text_search.py
+++ b/src/calibre/gui2/tweak_book/text_search.py
@@ -3,17 +3,12 @@
 
 
 from lxml.etree import tostring
-from qt.core import (
-    QCheckBox, QComboBox, QFont, QHBoxLayout, QIcon, QLabel, QPushButton, QSizePolicy,
-    QVBoxLayout, QWidget, pyqtSignal,
-)
+from qt.core import QCheckBox, QComboBox, QFont, QHBoxLayout, QIcon, QLabel, QPushButton, QSizePolicy, QVBoxLayout, QWidget, pyqtSignal
 
 from calibre import prepare_string_for_xml
 from calibre.gui2 import error_dialog
 from calibre.gui2.tweak_book import current_container, editors, tprefs
-from calibre.gui2.tweak_book.search import (
-    InvalidRegex, get_search_regex, initialize_search_request,
-)
+from calibre.gui2.tweak_book.search import InvalidRegex, get_search_regex, initialize_search_request
 from calibre.gui2.widgets import BusyCursor
 from calibre.gui2.widgets2 import HistoryComboBox
 from calibre.startup import connect_lambda
diff --git a/src/calibre/gui2/tweak_book/toc.py b/src/calibre/gui2/tweak_book/toc.py
index 19097a8e29..3f0a07cc8b 100644
--- a/src/calibre/gui2/tweak_book/toc.py
+++ b/src/calibre/gui2/tweak_book/toc.py
@@ -4,13 +4,28 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from qt.core import (
-    QAction, QApplication, QDialog, QDialogButtonBox, QGridLayout, QIcon, QMenu, QSize,
-    QStackedWidget, QStyledItemDelegate, Qt, QTimer, QTreeWidget, QTreeWidgetItem,
-    QVBoxLayout, QWidget, pyqtSignal,
-)
 from time import monotonic
 
+from qt.core import (
+    QAction,
+    QApplication,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QIcon,
+    QMenu,
+    QSize,
+    QStackedWidget,
+    QStyledItemDelegate,
+    Qt,
+    QTimer,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre.constants import ismacos
 from calibre.ebooks.oeb.polish.toc import commit_toc, get_toc
 from calibre.gui2 import error_dialog, info_dialog, make_view_use_window_background
diff --git a/src/calibre/gui2/tweak_book/ui.py b/src/calibre/gui2/tweak_book/ui.py
index 22be04cb16..cfaab76354 100644
--- a/src/calibre/gui2/tweak_book/ui.py
+++ b/src/calibre/gui2/tweak_book/ui.py
@@ -7,9 +7,25 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import os
 from functools import partial
 from itertools import product
+
 from qt.core import (
-    QAction, QDockWidget, QEvent, QHBoxLayout, QIcon, QLabel, QMenu, QMenuBar, QSize,
-    QStackedWidget, Qt, QTabWidget, QTimer, QUrl, QVBoxLayout, QWidget, pyqtSignal,
+    QAction,
+    QDockWidget,
+    QEvent,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QMenu,
+    QMenuBar,
+    QSize,
+    QStackedWidget,
+    Qt,
+    QTabWidget,
+    QTimer,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import prints
@@ -19,10 +35,7 @@ from calibre.gui2 import elided_text, open_url
 from calibre.gui2.keyboard import Manager as KeyboardManager
 from calibre.gui2.main_window import MainWindow
 from calibre.gui2.throbber import ThrobbingButton
-from calibre.gui2.tweak_book import (
-    actions, capitalize, current_container, editors, toolbar_actions, tprefs,
-    update_mark_text_action,
-)
+from calibre.gui2.tweak_book import actions, capitalize, current_container, editors, toolbar_actions, tprefs, update_mark_text_action
 from calibre.gui2.tweak_book.boss import Boss
 from calibre.gui2.tweak_book.char_select import CharSelect
 from calibre.gui2.tweak_book.check import Check
@@ -44,9 +57,7 @@ from calibre.gui2.tweak_book.toc import TOCViewer
 from calibre.gui2.tweak_book.undo import CheckpointView
 from calibre.gui2.widgets2 import MessagePopup
 from calibre.utils.icu import ord_string, sort_key
-from calibre.utils.localization import (
-    localize_user_manual_link, localize_website_link, pgettext,
-)
+from calibre.utils.localization import localize_user_manual_link, localize_website_link, pgettext
 from calibre.utils.unicode_names import character_name_from_code
 from polyglot.builtins import iteritems, itervalues
 
diff --git a/src/calibre/gui2/tweak_book/undo.py b/src/calibre/gui2/tweak_book/undo.py
index 804ad57a72..5dac2ba431 100644
--- a/src/calibre/gui2/tweak_book/undo.py
+++ b/src/calibre/gui2/tweak_book/undo.py
@@ -7,8 +7,19 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import shutil
 
 from qt.core import (
-    QAbstractListModel, Qt, QModelIndex, QApplication, QWidget,
-    QGridLayout, QListView, QStyledItemDelegate, pyqtSignal, QPushButton, QIcon, QItemSelectionModel)
+    QAbstractListModel,
+    QApplication,
+    QGridLayout,
+    QIcon,
+    QItemSelectionModel,
+    QListView,
+    QModelIndex,
+    QPushButton,
+    QStyledItemDelegate,
+    Qt,
+    QWidget,
+    pyqtSignal,
+)
 
 from calibre.gui2 import error_dialog
 
diff --git a/src/calibre/gui2/tweak_book/widgets.py b/src/calibre/gui2/tweak_book/widgets.py
index 1b492ae80f..0a1bba54ba 100644
--- a/src/calibre/gui2/tweak_book/widgets.py
+++ b/src/calibre/gui2/tweak_book/widgets.py
@@ -9,38 +9,63 @@ import textwrap
 import unicodedata
 from collections import OrderedDict
 from math import ceil
+
 from qt.core import (
-    QAbstractListModel, QApplication, QCheckBox, QComboBox, QDialog, QDialogButtonBox,
-    QEvent, QFormLayout, QFrame, QGridLayout, QGroupBox, QHBoxLayout, QIcon,
-    QItemSelectionModel, QLabel, QLineEdit, QListView, QMimeData, QModelIndex, QPainter,
-    QPalette, QPixmap, QPlainTextEdit, QPoint, QRect, QSize, QSizePolicy, QSplitter,
-    QStaticText, QStyle, QStyledItemDelegate, Qt, QTextCursor, QTextDocument,
-    QTextOption, QToolButton, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractListModel,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDialog,
+    QDialogButtonBox,
+    QEvent,
+    QFormLayout,
+    QFrame,
+    QGridLayout,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QItemSelectionModel,
+    QLabel,
+    QLineEdit,
+    QListView,
+    QMimeData,
+    QModelIndex,
+    QPainter,
+    QPalette,
+    QPixmap,
+    QPlainTextEdit,
+    QPoint,
+    QRect,
+    QSize,
+    QSizePolicy,
+    QSplitter,
+    QStaticText,
+    QStyle,
+    QStyledItemDelegate,
+    Qt,
+    QTextCursor,
+    QTextDocument,
+    QTextOption,
+    QToolButton,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import human_readable, prepare_string_for_xml
 from calibre.constants import iswindows
 from calibre.ebooks.oeb.polish.cover import get_raster_cover_name
-from calibre.ebooks.oeb.polish.toc import (
-    ensure_container_has_nav, get_guide_landmarks, get_nav_landmarks, set_landmarks,
-)
+from calibre.ebooks.oeb.polish.toc import ensure_container_has_nav, get_guide_landmarks, get_nav_landmarks, set_landmarks
 from calibre.ebooks.oeb.polish.upgrade import guide_epubtype_map
 from calibre.ebooks.oeb.polish.utils import guess_type, lead_text
-from calibre.gui2 import (
-    choose_files, choose_images, choose_save_file, error_dialog, info_dialog,
-)
+from calibre.gui2 import choose_files, choose_images, choose_save_file, error_dialog, info_dialog
 from calibre.gui2.complete2 import EditWithComplete
 from calibre.gui2.tweak_book import current_container, tprefs
-from calibre.gui2.widgets2 import (
-    PARAGRAPH_SEPARATOR, Dialog as BaseDialog, HistoryComboBox, to_plain_text,
-)
+from calibre.gui2.widgets2 import PARAGRAPH_SEPARATOR, HistoryComboBox, to_plain_text
+from calibre.gui2.widgets2 import Dialog as BaseDialog
 from calibre.startup import connect_lambda
-from calibre.utils.icu import (
-    numeric_sort_key, primary_contains, primary_sort_key, sort_key,
-)
-from calibre.utils.matcher import (
-    DEFAULT_LEVEL1, DEFAULT_LEVEL2, DEFAULT_LEVEL3, Matcher, get_char,
-)
+from calibre.utils.icu import numeric_sort_key, primary_contains, primary_sort_key, sort_key
+from calibre.utils.matcher import DEFAULT_LEVEL1, DEFAULT_LEVEL2, DEFAULT_LEVEL3, Matcher, get_char
 from polyglot.builtins import iteritems
 
 ROOT = QModelIndex()
diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index e1d438f9c0..ea91e925c1 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -8,7 +8,6 @@ __docformat__ = 'restructuredtext en'
 
 '''The main GUI'''
 
-import apsw
 import errno
 import gc
 import os
@@ -18,21 +17,27 @@ import textwrap
 import time
 from collections import OrderedDict, deque
 from io import BytesIO
-from qt.core import (
-    QAction, QApplication, QDialog, QFont, QIcon, QMenu, QSystemTrayIcon, Qt, QTimer,
-    QUrl, pyqtSignal,
-)
+
+import apsw
+from qt.core import QAction, QApplication, QDialog, QFont, QIcon, QMenu, QSystemTrayIcon, Qt, QTimer, QUrl, pyqtSignal
 
 from calibre import detect_ncpus, force_unicode, prints
-from calibre.constants import (
-    DEBUG, __appname__, config_dir, filesystem_encoding, ismacos, iswindows,
-)
+from calibre.constants import DEBUG, __appname__, config_dir, filesystem_encoding, ismacos, iswindows
 from calibre.customize import PluginInstallationType
 from calibre.customize.ui import available_store_plugins, interface_actions
 from calibre.db.legacy import LibraryDatabase
 from calibre.gui2 import (
-    Dispatcher, GetMetadata, config, error_dialog, gprefs, info_dialog,
-    max_available_height, open_url, question_dialog, timed_print, warning_dialog,
+    Dispatcher,
+    GetMetadata,
+    config,
+    error_dialog,
+    gprefs,
+    info_dialog,
+    max_available_height,
+    open_url,
+    question_dialog,
+    timed_print,
+    warning_dialog,
 )
 from calibre.gui2.auto_add import AutoAdder
 from calibre.gui2.changes import handle_changes
@@ -55,12 +60,13 @@ from calibre.gui2.search_box import SavedSearchBoxMixin, SearchBoxMixin
 from calibre.gui2.search_restriction_mixin import SearchRestrictionMixin
 from calibre.gui2.tag_browser.ui import TagBrowserMixin
 from calibre.gui2.update import UpdateMixin
-from calibre.gui2.widgets import ProgressIndicator, BusyCursor
+from calibre.gui2.widgets import BusyCursor, ProgressIndicator
 from calibre.library import current_library_name
 from calibre.srv.library_broker import GuiLibraryBroker, db_matches
 from calibre.utils.config import dynamic, prefs
 from calibre.utils.ipc.pool import Pool
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from polyglot.builtins import string_or_bytes
 from polyglot.queue import Empty, Queue
 
@@ -944,9 +950,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
                             det_msg=traceback.format_exc()
                             )
                     if repair:
-                        from calibre.gui2.dialogs.restore_library import (
-                            repair_library_at,
-                        )
+                        from calibre.gui2.dialogs.restore_library import repair_library_at
                         if repair_library_at(newloc, parent=self):
                             db = LibraryDatabase(newloc, default_prefs=default_prefs)
                         else:
diff --git a/src/calibre/gui2/update.py b/src/calibre/gui2/update.py
index 237f363734..61194cf5fd 100644
--- a/src/calibre/gui2/update.py
+++ b/src/calibre/gui2/update.py
@@ -3,16 +3,12 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 import ssl
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QObject, Qt, QUrl,
-    pyqtSignal,
-)
 from threading import Event, Thread
 
+from qt.core import QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QIcon, QLabel, QObject, Qt, QUrl, pyqtSignal
+
 from calibre import as_unicode, prints
-from calibre.constants import (
-    __appname__, __version__, ismacos, isportable, iswindows, numeric_version,
-)
+from calibre.constants import __appname__, __version__, ismacos, isportable, iswindows, numeric_version
 from calibre.gui2 import config, dynamic, icon_resource_manager, open_url
 from calibre.gui2.dialogs.plugin_updater import get_plugin_updates_available
 from calibre.utils.config import prefs
@@ -167,9 +163,7 @@ class UpdateNotification(QDialog):
         save_version_notified(calibre_version)
 
     def get_plugins(self):
-        from calibre.gui2.dialogs.plugin_updater import (
-            FILTER_UPDATE_AVAILABLE, PluginUpdaterDialog,
-        )
+        from calibre.gui2.dialogs.plugin_updater import FILTER_UPDATE_AVAILABLE, PluginUpdaterDialog
         d = PluginUpdaterDialog(self.parent(),
                 initial_filter=FILTER_UPDATE_AVAILABLE)
         d.exec()
@@ -237,9 +231,7 @@ class UpdateMixin:
                     self._update_notification__.show()
         elif has_plugin_updates:
             if force:
-                from calibre.gui2.dialogs.plugin_updater import (
-                    FILTER_UPDATE_AVAILABLE, PluginUpdaterDialog,
-                )
+                from calibre.gui2.dialogs.plugin_updater import FILTER_UPDATE_AVAILABLE, PluginUpdaterDialog
                 d = PluginUpdaterDialog(self,
                         initial_filter=FILTER_UPDATE_AVAILABLE)
                 d.exec()
diff --git a/src/calibre/gui2/viewer/bookmarks.py b/src/calibre/gui2/viewer/bookmarks.py
index 81146cb53a..eb3b9647ed 100644
--- a/src/calibre/gui2/viewer/bookmarks.py
+++ b/src/calibre/gui2/viewer/bookmarks.py
@@ -4,10 +4,23 @@
 
 import json
 from operator import itemgetter
+
 from qt.core import (
-    QAbstractItemView, QAction, QComboBox, QGridLayout, QHBoxLayout, QIcon,
-    QInputDialog, QItemSelectionModel, QLabel, QListWidget, QListWidgetItem,
-    QPushButton, Qt, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QAction,
+    QComboBox,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QItemSelectionModel,
+    QLabel,
+    QListWidget,
+    QListWidgetItem,
+    QPushButton,
+    Qt,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.gui2 import choose_files, choose_save_file, error_dialog
diff --git a/src/calibre/gui2/viewer/config.py b/src/calibre/gui2/viewer/config.py
index 02ee94bcdb..6d33d82ac9 100644
--- a/src/calibre/gui2/viewer/config.py
+++ b/src/calibre/gui2/viewer/config.py
@@ -111,7 +111,7 @@ def save_viewer_profile(profile_name, profile, *user_names: str):
         profile = json.loads(profile)
     if isinstance(profile, dict):
         profile['__timestamp__'] = isoformat(utcnow())
-        from calibre.gui2.viewer.toolbars import current_actions, DEFAULT_ACTIONS
+        from calibre.gui2.viewer.toolbars import DEFAULT_ACTIONS, current_actions
         ca = current_actions()
         s = {}
         if ca != DEFAULT_ACTIONS:
diff --git a/src/calibre/gui2/viewer/control_sleep.py b/src/calibre/gui2/viewer/control_sleep.py
index 3273846176..175019d437 100644
--- a/src/calibre/gui2/viewer/control_sleep.py
+++ b/src/calibre/gui2/viewer/control_sleep.py
@@ -5,10 +5,7 @@
 from calibre.constants import ismacos, iswindows
 
 if iswindows:
-    from calibre_extensions.winutil import (
-        ES_CONTINUOUS, ES_DISPLAY_REQUIRED, ES_SYSTEM_REQUIRED,
-        set_thread_execution_state
-    )
+    from calibre_extensions.winutil import ES_CONTINUOUS, ES_DISPLAY_REQUIRED, ES_SYSTEM_REQUIRED, set_thread_execution_state
 
     def prevent_sleep(reason=''):
         set_thread_execution_state(ES_CONTINUOUS | ES_DISPLAY_REQUIRED | ES_SYSTEM_REQUIRED)
@@ -17,10 +14,7 @@ if iswindows:
     def allow_sleep(cookie):
         set_thread_execution_state(ES_CONTINUOUS)
 elif ismacos:
-    from calibre_extensions.cocoa import (
-        create_io_pm_assertion, kIOPMAssertionTypeNoDisplaySleep,
-        release_io_pm_assertion
-    )
+    from calibre_extensions.cocoa import create_io_pm_assertion, kIOPMAssertionTypeNoDisplaySleep, release_io_pm_assertion
 
     def prevent_sleep(reason=''):
         return create_io_pm_assertion(kIOPMAssertionTypeNoDisplaySleep, reason or 'E-book viewer automated reading in progress')
diff --git a/src/calibre/gui2/viewer/highlights.py b/src/calibre/gui2/viewer/highlights.py
index da58a92fee..e7caedadcc 100644
--- a/src/calibre/gui2/viewer/highlights.py
+++ b/src/calibre/gui2/viewer/highlights.py
@@ -6,23 +6,44 @@ import math
 from collections import defaultdict
 from functools import lru_cache
 from itertools import chain
+
 from qt.core import (
-    QAbstractItemView, QColor, QDialog, QFont, QHBoxLayout, QIcon, QImage,
-    QItemSelectionModel, QKeySequence, QLabel, QMenu, QPainter, QPainterPath, QPalette,
-    QPixmap, QPushButton, QRect, QSizePolicy, QStyle, Qt, QTextCursor, QTextEdit,
-    QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QColor,
+    QDialog,
+    QFont,
+    QHBoxLayout,
+    QIcon,
+    QImage,
+    QItemSelectionModel,
+    QKeySequence,
+    QLabel,
+    QMenu,
+    QPainter,
+    QPainterPath,
+    QPalette,
+    QPixmap,
+    QPushButton,
+    QRect,
+    QSizePolicy,
+    QStyle,
+    Qt,
+    QTextCursor,
+    QTextEdit,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
 
-from calibre.constants import (
-    builtin_colors_dark, builtin_colors_light, builtin_decorations,
-)
+from calibre.constants import builtin_colors_dark, builtin_colors_light, builtin_decorations
 from calibre.ebooks.epub.cfi.parse import cfi_sort_key
 from calibre.gui2 import error_dialog, is_dark_theme, safe_open_url
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.gestures import GestureManager
-from calibre.gui2.library.annotations import (
-    ChapterGroup, Details, Export as ExportBase, render_notes,
-)
+from calibre.gui2.library.annotations import ChapterGroup, Details, render_notes
+from calibre.gui2.library.annotations import Export as ExportBase
 from calibre.gui2.viewer import get_boss, link_prefix_for_location_links
 from calibre.gui2.viewer.config import vprefs
 from calibre.gui2.viewer.search import SearchInput
diff --git a/src/calibre/gui2/viewer/integration.py b/src/calibre/gui2/viewer/integration.py
index 790e773114..b260d90a43 100644
--- a/src/calibre/gui2/viewer/integration.py
+++ b/src/calibre/gui2/viewer/integration.py
@@ -29,7 +29,8 @@ def database_has_annotations_support(cursor):
 
 def load_annotations_map_from_library(book_library_details, user_type='local', user='viewer'):
     import apsw
-    from calibre.db.backend import annotations_for_book, Connection
+
+    from calibre.db.backend import Connection, annotations_for_book
     ans = {}
     dbpath = book_library_details['dbpath']
     try:
@@ -53,9 +54,10 @@ def load_annotations_map_from_library(book_library_details, user_type='local', u
 
 def save_annotations_list_to_library(book_library_details, alist, sync_annots_user=''):
     import apsw
-    from calibre.db.backend import save_annotations_for_book, Connection, annotations_for_book
-    from calibre.gui2.viewer.annotations import annotations_as_copied_list
+
     from calibre.db.annotations import merge_annotations
+    from calibre.db.backend import Connection, annotations_for_book, save_annotations_for_book
+    from calibre.gui2.viewer.annotations import annotations_as_copied_list
     dbpath = book_library_details['dbpath']
     try:
         conn = apsw.Connection(dbpath, flags=apsw.SQLITE_OPEN_READWRITE)
diff --git a/src/calibre/gui2/viewer/lookup.py b/src/calibre/gui2/viewer/lookup.py
index 0af86a2104..dedd1701e3 100644
--- a/src/calibre/gui2/viewer/lookup.py
+++ b/src/calibre/gui2/viewer/lookup.py
@@ -5,15 +5,34 @@
 import sys
 import textwrap
 from functools import lru_cache
+
 from qt.core import (
-    QAbstractItemView, QApplication, QCheckBox, QComboBox, QDateTime, QDialog,
-    QDialogButtonBox, QFormLayout, QHBoxLayout, QIcon, QLabel, QLineEdit, QListWidget,
-    QListWidgetItem, QNetworkCookie, QPalette, QPushButton, QSize, Qt, QTimer, QUrl,
-    QVBoxLayout, QWidget, pyqtSignal,
-)
-from qt.webengine import (
-    QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineView,
+    QAbstractItemView,
+    QApplication,
+    QCheckBox,
+    QComboBox,
+    QDateTime,
+    QDialog,
+    QDialogButtonBox,
+    QFormLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QNetworkCookie,
+    QPalette,
+    QPushButton,
+    QSize,
+    Qt,
+    QTimer,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
 )
+from qt.webengine import QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineView
 
 from calibre import prints, random_user_agent
 from calibre.ebooks.metadata.sources.search_engines import google_consent_cookies
@@ -22,9 +41,7 @@ from calibre.gui2.viewer.web_view import apply_font_settings, vprefs
 from calibre.gui2.widgets2 import Dialog
 from calibre.utils.localization import _, canonicalize_lang, get_lang, lang_as_iso639_1
 from calibre.utils.resources import get_path as P
-from calibre.utils.webengine import (
-    create_script, insert_scripts, secure_webengine, setup_profile,
-)
+from calibre.utils.webengine import create_script, insert_scripts, secure_webengine, setup_profile
 
 
 @lru_cache
diff --git a/src/calibre/gui2/viewer/main.py b/src/calibre/gui2/viewer/main.py
index 491e67e545..022b5fb0b2 100644
--- a/src/calibre/gui2/viewer/main.py
+++ b/src/calibre/gui2/viewer/main.py
@@ -6,6 +6,7 @@ import json
 import os
 import sys
 from contextlib import closing
+
 from qt.core import QIcon, QObject, Qt, QTimer, pyqtSignal
 
 from calibre.constants import VIEWER_APP_UID, islinux
diff --git a/src/calibre/gui2/viewer/overlay.py b/src/calibre/gui2/viewer/overlay.py
index 6513e3e1ed..62af32ccc8 100644
--- a/src/calibre/gui2/viewer/overlay.py
+++ b/src/calibre/gui2/viewer/overlay.py
@@ -2,7 +2,7 @@
 # License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from qt.core import QWidget, Qt, QFontInfo, QLabel, QVBoxLayout, QPalette
+from qt.core import QFontInfo, QLabel, QPalette, Qt, QVBoxLayout, QWidget
 
 from calibre.gui2.progress_indicator import ProgressIndicator
 
diff --git a/src/calibre/gui2/viewer/printing.py b/src/calibre/gui2/viewer/printing.py
index 65d3c5860b..ea636a0e2e 100644
--- a/src/calibre/gui2/viewer/printing.py
+++ b/src/calibre/gui2/viewer/printing.py
@@ -5,17 +5,27 @@
 import os
 import subprocess
 import sys
-from qt.core import (
-    QCheckBox, QDialog, QDoubleSpinBox, QFormLayout, QHBoxLayout, QIcon, QLabel,
-    QLineEdit, QPageSize, QProgressDialog, QTimer, QToolButton, QVBoxLayout,
-)
 from threading import Thread
 
+from qt.core import (
+    QCheckBox,
+    QDialog,
+    QDoubleSpinBox,
+    QFormLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QPageSize,
+    QProgressDialog,
+    QTimer,
+    QToolButton,
+    QVBoxLayout,
+)
+
 from calibre import sanitize_file_name
 from calibre.ebooks.conversion.plugins.pdf_output import PAPER_SIZES
-from calibre.gui2 import (
-    Application, choose_save_file, dynamic, elided_text, error_dialog, open_local_file,
-)
+from calibre.gui2 import Application, choose_save_file, dynamic, elided_text, error_dialog, open_local_file
 from calibre.gui2.widgets import PaperSizes
 from calibre.gui2.widgets2 import Dialog
 from calibre.ptempfile import PersistentTemporaryFile
diff --git a/src/calibre/gui2/viewer/search.py b/src/calibre/gui2/viewer/search.py
index 8a6ce60741..c92d541b91 100644
--- a/src/calibre/gui2/viewer/search.py
+++ b/src/calibre/gui2/viewer/search.py
@@ -2,15 +2,29 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 import json
-import regex
 from collections import Counter, OrderedDict
 from html import escape
-from qt.core import (
-    QAbstractItemView, QCheckBox, QComboBox, QFont, QHBoxLayout, QIcon, QLabel, QMenu,
-    Qt, QToolButton, QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 
+import regex
+from qt.core import (
+    QAbstractItemView,
+    QCheckBox,
+    QComboBox,
+    QFont,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QMenu,
+    Qt,
+    QToolButton,
+    QTreeWidget,
+    QTreeWidgetItem,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre.ebooks.conversion.search_replace import REGEX_FLAGS
 from calibre.gui2 import warning_dialog
 from calibre.gui2.gestures import GestureManager
diff --git a/src/calibre/gui2/viewer/shortcuts.py b/src/calibre/gui2/viewer/shortcuts.py
index c6d21fda31..01b8ca327c 100644
--- a/src/calibre/gui2/viewer/shortcuts.py
+++ b/src/calibre/gui2/viewer/shortcuts.py
@@ -4,7 +4,6 @@
 
 from qt.core import QKeySequence, QMainWindow, Qt
 
-
 key_name_to_qt_name = {
     'ArrowRight': 'Right',
     'ArrowLeft': 'Left',
diff --git a/src/calibre/gui2/viewer/toc.py b/src/calibre/gui2/viewer/toc.py
index 5eca6cc0c0..925e0552f5 100644
--- a/src/calibre/gui2/viewer/toc.py
+++ b/src/calibre/gui2/viewer/toc.py
@@ -4,10 +4,25 @@
 
 import re
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QApplication, QEvent, QFont, QHBoxLayout, QIcon, QMenu,
-    QModelIndex, QStandardItem, QStandardItemModel, QStyledItemDelegate, Qt,
-    QToolButton, QToolTip, QTreeView, QWidget, pyqtSignal,
+    QAbstractItemView,
+    QApplication,
+    QEvent,
+    QFont,
+    QHBoxLayout,
+    QIcon,
+    QMenu,
+    QModelIndex,
+    QStandardItem,
+    QStandardItemModel,
+    QStyledItemDelegate,
+    Qt,
+    QToolButton,
+    QToolTip,
+    QTreeView,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre.gui2 import error_dialog
diff --git a/src/calibre/gui2/viewer/toolbars.py b/src/calibre/gui2/viewer/toolbars.py
index f8ebea7ed6..e5309462f0 100644
--- a/src/calibre/gui2/viewer/toolbars.py
+++ b/src/calibre/gui2/viewer/toolbars.py
@@ -4,10 +4,26 @@
 
 import os
 from functools import partial
+
 from qt.core import (
-    QAbstractItemView, QAction, QDialog, QDialogButtonBox, QGroupBox, QHBoxLayout,
-    QIcon, QInputDialog, QKeySequence, QLabel, QListWidget, QListWidgetItem, QMenu, Qt,
-    QToolBar, QToolButton, QVBoxLayout, pyqtSignal,
+    QAbstractItemView,
+    QAction,
+    QDialog,
+    QDialogButtonBox,
+    QGroupBox,
+    QHBoxLayout,
+    QIcon,
+    QInputDialog,
+    QKeySequence,
+    QLabel,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    Qt,
+    QToolBar,
+    QToolButton,
+    QVBoxLayout,
+    pyqtSignal,
 )
 from qt.webengine import QWebEnginePage
 
diff --git a/src/calibre/gui2/viewer/ui.py b/src/calibre/gui2/viewer/ui.py
index a493df7977..4061ae8b3e 100644
--- a/src/calibre/gui2/viewer/ui.py
+++ b/src/calibre/gui2/viewer/ui.py
@@ -8,36 +8,43 @@ import sys
 import time
 from collections import defaultdict, namedtuple
 from hashlib import sha256
+from threading import Thread
+
 from qt.core import (
-    QApplication, QCursor, QDockWidget, QEvent, QMainWindow, QMenu, QMimeData,
-    QModelIndex, QPixmap, Qt, QTimer, QToolBar, QUrl, QVBoxLayout, QWidget, pyqtSignal,
+    QApplication,
+    QCursor,
+    QDockWidget,
+    QEvent,
+    QMainWindow,
+    QMenu,
+    QMimeData,
+    QModelIndex,
+    QPixmap,
+    Qt,
+    QTimer,
+    QToolBar,
+    QUrl,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
     sip,
 )
-from threading import Thread
 
 from calibre import prints
 from calibre.constants import ismacos, iswindows
 from calibre.customize.ui import available_input_formats
 from calibre.db.annotations import merge_annotations
-from calibre.gui2 import (
-    add_to_recent_docs, choose_files, error_dialog, sanitize_env_vars,
-)
+from calibre.gui2 import add_to_recent_docs, choose_files, error_dialog, sanitize_env_vars
 from calibre.gui2.dialogs.drm_error import DRMErrorMessage
 from calibre.gui2.image_popup import ImagePopup
 from calibre.gui2.main_window import MainWindow
 from calibre.gui2.viewer import get_boss, get_current_book_data, performance_monitor
-from calibre.gui2.viewer.annotations import (
-    AnnotationsSaveWorker, annotations_dir, parse_annotations,
-)
+from calibre.gui2.viewer.annotations import AnnotationsSaveWorker, annotations_dir, parse_annotations
 from calibre.gui2.viewer.bookmarks import BookmarkManager
-from calibre.gui2.viewer.config import (
-    get_session_pref, load_reading_rates, save_reading_rates, vprefs,
-)
+from calibre.gui2.viewer.config import get_session_pref, load_reading_rates, save_reading_rates, vprefs
 from calibre.gui2.viewer.convert_book import clean_running_workers, prepare_book
 from calibre.gui2.viewer.highlights import HighlightsPanel
-from calibre.gui2.viewer.integration import (
-    get_book_library_details, load_annotations_map_from_library,
-)
+from calibre.gui2.viewer.integration import get_book_library_details, load_annotations_map_from_library
 from calibre.gui2.viewer.lookup import Lookup
 from calibre.gui2.viewer.overlay import LoadingOverlay
 from calibre.gui2.viewer.search import SearchPanel
diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index ec91e08684..1969c853f4 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -5,29 +5,43 @@ import os
 import shutil
 import sys
 from itertools import count
+
 from qt.core import (
-    QT_VERSION, QApplication, QByteArray, QEvent, QFontDatabase, QFontInfo, QHBoxLayout,
-    QLocale, QMimeData, QPalette, QSize, Qt, QTimer, QUrl, QWidget, pyqtSignal, sip,
+    QT_VERSION,
+    QApplication,
+    QByteArray,
+    QEvent,
+    QFontDatabase,
+    QFontInfo,
+    QHBoxLayout,
+    QLocale,
+    QMimeData,
+    QPalette,
+    QSize,
+    Qt,
+    QTimer,
+    QUrl,
+    QWidget,
+    pyqtSignal,
+    sip,
 )
 from qt.webengine import (
-    QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineSettings,
-    QWebEngineUrlRequestJob, QWebEngineUrlSchemeHandler, QWebEngineView,
+    QWebEnginePage,
+    QWebEngineProfile,
+    QWebEngineScript,
+    QWebEngineSettings,
+    QWebEngineUrlRequestJob,
+    QWebEngineUrlSchemeHandler,
+    QWebEngineView,
 )
 
 from calibre import as_unicode, prints
-from calibre.constants import (
-    FAKE_HOST, FAKE_PROTOCOL, __version__, in_develop_mode, is_running_from_develop,
-    ismacos, iswindows,
-)
+from calibre.constants import FAKE_HOST, FAKE_PROTOCOL, __version__, in_develop_mode, is_running_from_develop, ismacos, iswindows
 from calibre.ebooks.metadata.book.base import field_metadata
 from calibre.ebooks.oeb.polish.utils import guess_type
 from calibre.gui2 import choose_images, config, error_dialog, safe_open_url
-from calibre.gui2.viewer import (
-    link_prefix_for_location_links, performance_monitor, url_for_book_in_library,
-)
-from calibre.gui2.viewer.config import (
-    load_viewer_profiles, save_viewer_profile, viewer_config_dir, vprefs,
-)
+from calibre.gui2.viewer import link_prefix_for_location_links, performance_monitor, url_for_book_in_library
+from calibre.gui2.viewer.config import load_viewer_profiles, save_viewer_profile, viewer_config_dir, vprefs
 from calibre.gui2.viewer.tts import TTS
 from calibre.gui2.webengine import RestartingWebEngineView
 from calibre.srv.code import get_translations_data
@@ -36,10 +50,7 @@ from calibre.utils.localization import _, localize_user_manual_link
 from calibre.utils.resources import get_path as P
 from calibre.utils.serialize import json_loads
 from calibre.utils.shared_file import share_open
-from calibre.utils.webengine import (
-    Bridge, create_script, from_js, insert_scripts, secure_webengine, send_reply,
-    setup_profile, to_js,
-)
+from calibre.utils.webengine import Bridge, create_script, from_js, insert_scripts, secure_webengine, send_reply, setup_profile, to_js
 from polyglot.builtins import as_bytes, iteritems
 from polyglot.functools import lru_cache
 
diff --git a/src/calibre/gui2/viewer/widgets.py b/src/calibre/gui2/viewer/widgets.py
index 514fa4e20c..2c8c704f93 100644
--- a/src/calibre/gui2/viewer/widgets.py
+++ b/src/calibre/gui2/viewer/widgets.py
@@ -2,9 +2,8 @@
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
 import re
-from qt.core import (
-    QAction, QFont, QFontMetrics, QPalette, QStyle, QStyledItemDelegate, Qt, pyqtSignal,
-)
+
+from qt.core import QAction, QFont, QFontMetrics, QPalette, QStyle, QStyledItemDelegate, Qt, pyqtSignal
 
 from calibre.gui2 import QT_HIDDEN_CLEAR_ACTION
 from calibre.gui2.widgets2 import HistoryComboBox
diff --git a/src/calibre/gui2/widgets.py b/src/calibre/gui2/widgets.py
index 8211d542f9..833c586570 100644
--- a/src/calibre/gui2/widgets.py
+++ b/src/calibre/gui2/widgets.py
@@ -5,22 +5,46 @@ Miscellaneous widgets used in the GUI
 '''
 import os
 import re
+
 from qt.core import (
-    QApplication, QClipboard, QColor, QComboBox, QCompleter, QCursor, QEvent, QFont,
-    QGraphicsScene, QGraphicsView, QIcon, QLabel, QLineEdit, QListWidget,
-    QListWidgetItem, QMenu, QPageSize, QPainter, QPalette, QPen, QPixmap, QPrinter,
-    QRect, QSize, QSplitterHandle, QStringListModel, QSyntaxHighlighter, Qt,
-    QTextCharFormat, QWidget, pyqtSignal,
+    QApplication,
+    QClipboard,
+    QColor,
+    QComboBox,
+    QCompleter,
+    QCursor,
+    QEvent,
+    QFont,
+    QGraphicsScene,
+    QGraphicsView,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QListWidget,
+    QListWidgetItem,
+    QMenu,
+    QPageSize,
+    QPainter,
+    QPalette,
+    QPen,
+    QPixmap,
+    QPrinter,
+    QRect,
+    QSize,
+    QSplitterHandle,
+    QStringListModel,
+    QSyntaxHighlighter,
+    Qt,
+    QTextCharFormat,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import fit_image, force_unicode, strftime
 from calibre.constants import ismacos, iswindows
 from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.gui2 import error_dialog, gprefs, pixmap_to_data, warning_dialog
-from calibre.gui2.dnd import (
-    DownloadDialog, dnd_get_files, dnd_get_image, dnd_get_local_image_and_pixmap,
-    dnd_has_extension, dnd_has_image, image_extensions,
-)
+from calibre.gui2.dnd import DownloadDialog, dnd_get_files, dnd_get_image, dnd_get_local_image_and_pixmap, dnd_has_extension, dnd_has_image, image_extensions
 from calibre.gui2.filename_pattern_ui import Ui_Form
 from calibre.gui2.progress_indicator import ProgressIndicator as _ProgressIndicator
 from calibre.startup import connect_lambda
diff --git a/src/calibre/gui2/widgets2.py b/src/calibre/gui2/widgets2.py
index 6040479314..bc3ff90242 100644
--- a/src/calibre/gui2/widgets2.py
+++ b/src/calibre/gui2/widgets2.py
@@ -3,22 +3,62 @@
 
 
 import weakref
+
 from qt.core import (
-    QApplication, QBrush, QByteArray, QCalendarWidget, QCheckBox, QColor, QColorDialog,
-    QComboBox, QDate, QDateTime, QDateTimeEdit, QDialog, QDialogButtonBox, QFont,
-    QFontInfo, QFontMetrics, QFrame, QIcon, QKeySequence, QLabel, QLayout, QMenu,
-    QMimeData, QPainter, QPalette, QPixmap, QPoint, QPushButton, QRect, QScrollArea,
-    QSize, QSizePolicy, QStyle, QStyledItemDelegate, QStyleOptionToolButton,
-    QStylePainter, Qt, QTabWidget, QTextBrowser, QTextCursor, QTextDocument, QTimer,
-    QToolButton, QUndoCommand, QUndoStack, QUrl, QWidget, pyqtSignal,
+    QApplication,
+    QBrush,
+    QByteArray,
+    QCalendarWidget,
+    QCheckBox,
+    QColor,
+    QColorDialog,
+    QComboBox,
+    QDate,
+    QDateTime,
+    QDateTimeEdit,
+    QDialog,
+    QDialogButtonBox,
+    QFont,
+    QFontInfo,
+    QFontMetrics,
+    QFrame,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QLayout,
+    QMenu,
+    QMimeData,
+    QPainter,
+    QPalette,
+    QPixmap,
+    QPoint,
+    QPushButton,
+    QRect,
+    QScrollArea,
+    QSize,
+    QSizePolicy,
+    QStyle,
+    QStyledItemDelegate,
+    QStyleOptionToolButton,
+    QStylePainter,
+    Qt,
+    QTabWidget,
+    QTextBrowser,
+    QTextCursor,
+    QTextDocument,
+    QTimer,
+    QToolButton,
+    QUndoCommand,
+    QUndoStack,
+    QUrl,
+    QWidget,
+    pyqtSignal,
 )
 
 from calibre import prepare_string_for_xml
 from calibre.constants import builtin_colors_dark, builtin_colors_light
 from calibre.ebooks.metadata import rating_to_stars
-from calibre.gui2 import (
-    UNDEFINED_QDATETIME, gprefs, local_path_for_resource, rating_font,
-)
+from calibre.gui2 import UNDEFINED_QDATETIME, gprefs, local_path_for_resource, rating_font
 from calibre.gui2.complete2 import EditWithComplete, LineEdit
 from calibre.gui2.widgets import history
 from calibre.utils.config_base import tweaks
diff --git a/src/calibre/gui2/wizard/__init__.py b/src/calibre/gui2/wizard/__init__.py
index 1e42eabb0e..07105dee15 100644
--- a/src/calibre/gui2/wizard/__init__.py
+++ b/src/calibre/gui2/wizard/__init__.py
@@ -9,10 +9,8 @@ import os
 import re
 import traceback
 from contextlib import closing, suppress
-from qt.core import (
-    QAbstractListModel, QDir, QIcon, QItemSelection, QItemSelectionModel, Qt, QWizard,
-    QWizardPage, pyqtSignal,
-)
+
+from qt.core import QAbstractListModel, QDir, QIcon, QItemSelection, QItemSelectionModel, Qt, QWizard, QWizardPage, pyqtSignal
 
 from calibre import __appname__
 from calibre.constants import filesystem_encoding, isportable, iswindows
@@ -716,9 +714,7 @@ class LibraryPage(QWizardPage, LibraryUI):
     def init_languages(self):
         self.language.blockSignals(True)
         self.language.clear()
-        from calibre.utils.localization import (
-            available_translations, get_lang, get_language, get_lc_messages_path,
-        )
+        from calibre.utils.localization import available_translations, get_lang, get_language, get_lc_messages_path
         lang = get_lang()
         lang = get_lc_messages_path(lang) if lang else lang
         if lang is None or lang not in available_translations():
diff --git a/src/calibre/gui2/wizard/send_email.py b/src/calibre/gui2/wizard/send_email.py
index 8249790939..c3df40de94 100644
--- a/src/calibre/gui2/wizard/send_email.py
+++ b/src/calibre/gui2/wizard/send_email.py
@@ -7,12 +7,25 @@ __docformat__ = 'restructuredtext en'
 
 import sys
 from functools import partial
-from qt.core import (
-    QCheckBox, QDialog, QDialogButtonBox, QGridLayout, QHBoxLayout, QIcon, QLabel,
-    QLineEdit, QPlainTextEdit, QPushButton, Qt, QVBoxLayout, QWidget, pyqtSignal,
-)
 from threading import Thread
 
+from qt.core import (
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QGridLayout,
+    QHBoxLayout,
+    QIcon,
+    QLabel,
+    QLineEdit,
+    QPlainTextEdit,
+    QPushButton,
+    Qt,
+    QVBoxLayout,
+    QWidget,
+    pyqtSignal,
+)
+
 from calibre import prints
 from calibre.gui2 import error_dialog, question_dialog
 from calibre.gui2.wizard.send_email_ui import Ui_Form
diff --git a/src/calibre/gui_launch.py b/src/calibre/gui_launch.py
index e0bf492d2b..482ac877cf 100644
--- a/src/calibre/gui_launch.py
+++ b/src/calibre/gui_launch.py
@@ -4,7 +4,8 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, sys
+import os
+import sys
 
 # For some reason Qt 5 crashes on some linux systems if the fork() is done
 # after the Qt modules are loaded in calibre.gui2. We also cannot do a fork()
@@ -39,7 +40,7 @@ qt.webenginecontext.info=false
 
 
 def detach_gui():
-    from calibre.constants import islinux, isbsd, DEBUG
+    from calibre.constants import DEBUG, isbsd, islinux
     if (islinux or isbsd) and not DEBUG and '--detach' in sys.argv:
         do_detach()
 
@@ -47,8 +48,8 @@ def detach_gui():
 def register_with_default_programs():
     from calibre.constants import iswindows
     if iswindows:
-        from calibre.utils.winreg.default_programs import Register
         from calibre.gui2 import gprefs
+        from calibre.utils.winreg.default_programs import Register
         return Register(gprefs)
     else:
         class Dummy:
@@ -74,8 +75,9 @@ def calibre(args=sys.argv):
 
 
 def is_possible_media_pack_error(e):
-    from calibre.constants import iswindows
     from ctypes.util import find_library
+
+    from calibre.constants import iswindows
     if iswindows and 'QtWebEngine' in str(e):
         if not find_library('MFTranscode.dll'):
             return True
@@ -84,7 +86,8 @@ def is_possible_media_pack_error(e):
 
 def show_media_pack_error():
     import traceback
-    from calibre.gui2 import error_dialog, Application
+
+    from calibre.gui2 import Application, error_dialog
     from calibre.utils.localization import _
     app = Application([])
     error_dialog(None, _('Required component missing'), '<p>' + _(
diff --git a/src/calibre/library/__init__.py b/src/calibre/library/__init__.py
index 6b9978a8be..6ffac893bc 100644
--- a/src/calibre/library/__init__.py
+++ b/src/calibre/library/__init__.py
@@ -24,7 +24,12 @@ def generate_test_db(library_path,  # {{{
         max_authors=10,
         max_tags=10
         ):
-    import random, string, os, sys, time
+    import os
+    import random
+    import string
+    import sys
+    import time
+
     from calibre.constants import preferred_encoding
 
     if not os.path.exists(library_path):
diff --git a/src/calibre/library/catalogs/epub_mobi.py b/src/calibre/library/catalogs/epub_mobi.py
index ae95691c71..a5ae05c83c 100644
--- a/src/calibre/library/catalogs/epub_mobi.py
+++ b/src/calibre/library/catalogs/epub_mobi.py
@@ -16,9 +16,7 @@ from calibre.customize.conversion import DummyReporter, OptionRecommendation
 from calibre.library import current_library_name
 from calibre.library.catalogs import AuthorSortMismatchException, EmptyCatalogException
 from calibre.ptempfile import PersistentTemporaryFile
-from calibre.utils.localization import (
-    _, calibre_langcode_to_name, canonicalize_lang, get_lang,
-)
+from calibre.utils.localization import _, calibre_langcode_to_name, canonicalize_lang, get_lang
 
 Option = namedtuple('Option', 'option, default, dest, action, help')
 
diff --git a/src/calibre/library/catalogs/epub_mobi_builder.py b/src/calibre/library/catalogs/epub_mobi_builder.py
index ad26ab615d..246e7d835e 100644
--- a/src/calibre/library/catalogs/epub_mobi_builder.py
+++ b/src/calibre/library/catalogs/epub_mobi_builder.py
@@ -10,13 +10,11 @@ import time
 import unicodedata
 import zlib
 from copy import deepcopy
-from lxml import etree
 from xml.sax.saxutils import escape
 
-from calibre import (
-    as_unicode, force_unicode, isbytestring, prepare_string_for_xml, replace_entities,
-    strftime, xml_replace_entities,
-)
+from lxml import etree
+
+from calibre import as_unicode, force_unicode, isbytestring, prepare_string_for_xml, replace_entities, strftime, xml_replace_entities
 from calibre.constants import cache_dir, ismacos
 from calibre.customize.conversion import DummyReporter
 from calibre.customize.ui import output_profiles
@@ -24,22 +22,19 @@ from calibre.ebooks.BeautifulSoup import BeautifulSoup, NavigableString, prettif
 from calibre.ebooks.chardet import substitute_entites
 from calibre.ebooks.metadata import author_to_author_sort
 from calibre.ebooks.oeb.polish.pretty import pretty_opf, pretty_xml_tree
-from calibre.library.catalogs import (
-    AuthorSortMismatchException, EmptyCatalogException,
-    InvalidGenresSourceFieldException,
-)
+from calibre.library.catalogs import AuthorSortMismatchException, EmptyCatalogException, InvalidGenresSourceFieldException
 from calibre.library.comments import comments_to_html
 from calibre.ptempfile import PersistentTemporaryDirectory
-from calibre.utils.date import (
-    as_local_time, format_date, is_date_undefined, now as nowf, utcfromtimestamp,
-)
+from calibre.utils.date import as_local_time, format_date, is_date_undefined, utcfromtimestamp
+from calibre.utils.date import now as nowf
 from calibre.utils.filenames import ascii_text, shorten_components_to
 from calibre.utils.formatter import TemplateFormatter
-from calibre.utils.icu import (
-    capitalize, collation_order, sort_key, title_case as icu_title, upper as icu_upper,
-)
+from calibre.utils.icu import capitalize, collation_order, sort_key
+from calibre.utils.icu import title_case as icu_title
+from calibre.utils.icu import upper as icu_upper
 from calibre.utils.localization import _, get_lang, lang_as_iso639_1, ngettext
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.utils.zipfile import ZipFile
 from polyglot.builtins import iteritems
diff --git a/src/calibre/library/check_library.py b/src/calibre/library/check_library.py
index cc94864249..90b80d3ac0 100644
--- a/src/calibre/library/check_library.py
+++ b/src/calibre/library/check_library.py
@@ -12,9 +12,7 @@ import traceback
 
 from calibre import isbytestring
 from calibre.constants import filesystem_encoding
-from calibre.db.constants import (
-    COVER_FILE_NAME, DATA_DIR_NAME, METADATA_FILE_NAME, TRASH_DIR_NAME, NOTES_DIR_NAME,
-)
+from calibre.db.constants import COVER_FILE_NAME, DATA_DIR_NAME, METADATA_FILE_NAME, NOTES_DIR_NAME, TRASH_DIR_NAME
 from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.utils.localization import _
 from polyglot.builtins import iteritems
diff --git a/src/calibre/library/comments.py b/src/calibre/library/comments.py
index 21320e28cc..ba4e8a581e 100644
--- a/src/calibre/library/comments.py
+++ b/src/calibre/library/comments.py
@@ -6,10 +6,7 @@ import re
 
 from calibre import prepare_string_for_xml
 from calibre.constants import preferred_encoding
-from calibre.ebooks.BeautifulSoup import (
-    BeautifulSoup, CData, Comment, Declaration, NavigableString,
-    ProcessingInstruction
-)
+from calibre.ebooks.BeautifulSoup import BeautifulSoup, CData, Comment, Declaration, NavigableString, ProcessingInstruction
 from calibre.utils.html2text import html2text
 
 # Hackish - ignoring sentences ending or beginning in numbers to avoid
diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 79cb6aaf75..ef8d4d1c2a 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -26,20 +26,13 @@ from collections import defaultdict, namedtuple
 from calibre import force_unicode, isbytestring, prints
 from calibre.constants import filesystem_encoding, iswindows, preferred_encoding
 from calibre.customize.ui import run_plugins_on_import, run_plugins_on_postimport
-from calibre.db import (
-    _get_next_series_num_for_list, _get_series_values, get_data_as_dict,
-)
-from calibre.db.adding import (
-    find_books_in_directory, import_book_directory, import_book_directory_multiple,
-    recursive_import,
-)
+from calibre.db import _get_next_series_num_for_list, _get_series_values, get_data_as_dict
+from calibre.db.adding import find_books_in_directory, import_book_directory, import_book_directory_multiple, recursive_import
 from calibre.db.categories import CATEGORY_SORTS, Tag
 from calibre.db.errors import NoSuchFormat
 from calibre.db.lazy import FormatMetadata, FormatsList
 from calibre.ebooks import check_ebook_format
-from calibre.ebooks.metadata import (
-    author_to_author_sort, get_title_sort_pat, string_to_authors, title_sort,
-)
+from calibre.ebooks.metadata import author_to_author_sort, get_title_sort_pat, string_to_authors, title_sort
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
 from calibre.library.caches import ResultCache
@@ -51,14 +44,12 @@ from calibre.library.schema_upgrades import SchemaUpgrade
 from calibre.library.sqlite import IntegrityError, connect
 from calibre.ptempfile import PersistentTemporaryFile, SpooledTemporaryFile, base_dir
 from calibre.utils.config import from_json, prefs, to_json, tweaks
-from calibre.utils.date import (
-    UNDEFINED_DATE, now as nowf, parse_date, parse_only_date, utcfromtimestamp, utcnow,
-)
-from calibre.utils.filenames import (
-    WindowsAtomicFolderMove, ascii_filename, hardlink_file, samefile,
-)
+from calibre.utils.date import UNDEFINED_DATE, parse_date, parse_only_date, utcfromtimestamp, utcnow
+from calibre.utils.date import now as nowf
+from calibre.utils.filenames import WindowsAtomicFolderMove, ascii_filename, hardlink_file, samefile
 from calibre.utils.formatter_functions import load_user_template_functions
-from calibre.utils.icu import lower, lower as icu_lower, sort_key, strcmp
+from calibre.utils.icu import lower, sort_key, strcmp
+from calibre.utils.icu import lower as icu_lower
 from calibre.utils.img import save_cover_data_to
 from calibre.utils.localization import _, calibre_langcode_to_name, canonicalize_lang
 from calibre.utils.recycle_bin import delete_file, delete_tree
diff --git a/src/calibre/library/prefs.py b/src/calibre/library/prefs.py
index a28da7df55..08f6b9daa8 100644
--- a/src/calibre/library/prefs.py
+++ b/src/calibre/library/prefs.py
@@ -5,11 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import json, os
+import json
+import os
 
-from calibre.constants import preferred_encoding
-from calibre.utils.config import to_json, from_json
 from calibre import prints
+from calibre.constants import preferred_encoding
+from calibre.utils.config import from_json, to_json
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/library/save_to_disk.py b/src/calibre/library/save_to_disk.py
index b0a4785a80..9485189666 100644
--- a/src/calibre/library/save_to_disk.py
+++ b/src/calibre/library/save_to_disk.py
@@ -16,9 +16,7 @@ from calibre.db.lazy import FormatsList
 from calibre.ebooks.metadata import fmt_sidx, title_sort
 from calibre.utils.config import Config, StringConfig, tweaks
 from calibre.utils.date import as_local_time, is_date_undefined
-from calibre.utils.filenames import (
-    ascii_filename, make_long_path_useable, shorten_components_to,
-)
+from calibre.utils.filenames import ascii_filename, make_long_path_useable, shorten_components_to
 from calibre.utils.formatter import TemplateFormatter
 from calibre.utils.formatter_functions import load_user_template_functions
 from calibre.utils.localization import _
diff --git a/src/calibre/library/schema_upgrades.py b/src/calibre/library/schema_upgrades.py
index d4db2275ba..58619f87f0 100644
--- a/src/calibre/library/schema_upgrades.py
+++ b/src/calibre/library/schema_upgrades.py
@@ -7,7 +7,7 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.utils.date import isoformat, DEFAULT_DATE
+from calibre.utils.date import DEFAULT_DATE, isoformat
 from polyglot.builtins import itervalues
 
 
@@ -585,8 +585,7 @@ class SchemaUpgrade:
     def upgrade_version_19(self):
         recipes = self.conn.get('SELECT id,title,script FROM feeds')
         if recipes:
-            from calibre.web.feeds.recipes import custom_recipes, \
-                    custom_recipe_filename
+            from calibre.web.feeds.recipes import custom_recipe_filename, custom_recipes
             bdir = os.path.dirname(custom_recipes.file_path)
             for id_, title, script in recipes:
                 existing = frozenset(map(int, custom_recipes))
diff --git a/src/calibre/library/sqlite.py b/src/calibre/library/sqlite.py
index e6201a2b1b..8b195860e8 100644
--- a/src/calibre/library/sqlite.py
+++ b/src/calibre/library/sqlite.py
@@ -7,25 +7,26 @@ Wrapper for multi-threaded access to a single sqlite database connection. Serial
 all calls.
 '''
 
-import sqlite3 as sqlite, traceback, time, uuid, os
-from sqlite3 import IntegrityError, OperationalError
-from threading import Thread
-from threading import RLock
+import os
+import sqlite3 as sqlite
+import time
+import traceback
+import uuid
 from datetime import datetime, timezone
 from functools import partial
+from sqlite3 import IntegrityError, OperationalError
+from threading import RLock, Thread
 
-from calibre.ebooks.metadata import title_sort, author_to_author_sort
-from calibre.utils.date import parse_date, isoformat, local_tz, UNDEFINED_DATE
-from calibre import isbytestring, force_unicode
-from calibre.constants import iswindows, DEBUG, plugins_loc, plugins
+from calibre import force_unicode, isbytestring, prints
+from calibre.constants import DEBUG, iswindows, plugins, plugins_loc
+from calibre.ebooks.metadata import author_to_author_sort, title_sort
+from calibre.utils.date import UNDEFINED_DATE, isoformat, local_tz, parse_date
 from calibre.utils.icu import sort_key
 from calibre_extensions import speedup as _c_speedup
-from calibre import prints
-from polyglot.builtins import cmp, native_string_type
 from polyglot import reprlib
+from polyglot.builtins import cmp, native_string_type
 from polyglot.queue import Queue
 
-
 global_lock = RLock()
 
 
diff --git a/src/calibre/libunzip.py b/src/calibre/libunzip.py
index 06124619ac..0138826a21 100644
--- a/src/calibre/libunzip.py
+++ b/src/calibre/libunzip.py
@@ -5,6 +5,7 @@ __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
 
 import re
+
 from calibre.utils import zipfile
 from calibre.utils.icu import numeric_sort_key
 
diff --git a/src/calibre/linux.py b/src/calibre/linux.py
index 2a2b9e2e83..719420b4b5 100644
--- a/src/calibre/linux.py
+++ b/src/calibre/linux.py
@@ -16,7 +16,8 @@ from calibre.constants import isbsd, islinux
 from calibre.customize.ui import all_input_formats
 from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.localization import _
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from polyglot.builtins import iteritems
 
 entry_points = {
@@ -576,12 +577,12 @@ def write_completion(self, bash_comp_dest, zsh):
     from calibre.debug import option_parser as debug_op
     from calibre.ebooks import BOOK_EXTENSIONS
     from calibre.ebooks.lrf.lrfparser import option_parser as lrf2lrsop
-    from calibre.ebooks.metadata.cli import (
-        filetypes as meta_filetypes, option_parser as metaop,
-    )
+    from calibre.ebooks.metadata.cli import filetypes as meta_filetypes
+    from calibre.ebooks.metadata.cli import option_parser as metaop
     from calibre.ebooks.metadata.sources.cli import option_parser as fem_op
     from calibre.ebooks.oeb.polish.import_book import IMPORTABLE
-    from calibre.ebooks.oeb.polish.main import SUPPORTED, option_parser as polish_op
+    from calibre.ebooks.oeb.polish.main import SUPPORTED
+    from calibre.ebooks.oeb.polish.main import option_parser as polish_op
     from calibre.gui2.lrf_renderer.main import option_parser as lrfviewerop
     from calibre.gui2.main import option_parser as guiop
     from calibre.gui2.tweak_book.main import option_parser as tweak_op
@@ -1215,6 +1216,7 @@ def changelog_bullet_to_text(bullet):
 
 def make_appdata_releases():
     import json
+
     from lxml.builder import E
     changelog = json.loads(P('changelog.json', data=True))
 
diff --git a/src/calibre/live.py b/src/calibre/live.py
index a1e9245326..ea6680dcab 100644
--- a/src/calibre/live.py
+++ b/src/calibre/live.py
@@ -1,7 +1,6 @@
 #!/usr/bin/env python
 # License: GPL v3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
 
-import apsw
 import ast
 import gzip
 import os
@@ -16,6 +15,8 @@ from importlib import import_module
 from queue import Queue
 from threading import Lock, Thread
 
+import apsw
+
 from calibre.constants import cache_dir, numeric_version
 from calibre.utils.date import utcnow
 from calibre.utils.https import HTTPError, get_https_resource_securely
@@ -254,9 +255,9 @@ def load_module(full_name, strategy=Strategy.download_now, timeout=default_timeo
 
 
 def find_tests():
+    import hashlib
     import tempfile
     import unittest
-    import hashlib
 
     class LiveTest(unittest.TestCase):
         ae = unittest.TestCase.assertEqual
diff --git a/src/calibre/ptempfile.py b/src/calibre/ptempfile.py
index c0588dbb64..3fb5f87783 100644
--- a/src/calibre/ptempfile.py
+++ b/src/calibre/ptempfile.py
@@ -4,10 +4,11 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 Provides platform independent temporary files that persist even after
 being closed.
 """
-import tempfile, os, atexit
+import atexit
+import os
+import tempfile
 
-from calibre.constants import (__version__, __appname__, filesystem_encoding,
-        iswindows, get_windows_temp_path, ismacos)
+from calibre.constants import __appname__, __version__, filesystem_encoding, get_windows_temp_path, ismacos, iswindows
 
 
 def cleanup(path):
diff --git a/src/calibre/rpdb.py b/src/calibre/rpdb.py
index 621ff45549..f904c32e51 100644
--- a/src/calibre/rpdb.py
+++ b/src/calibre/rpdb.py
@@ -4,7 +4,14 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import pdb, socket, inspect, sys, select, os, atexit, time
+import atexit
+import inspect
+import os
+import pdb
+import select
+import socket
+import sys
+import time
 from contextlib import suppress
 
 from calibre.constants import cache_dir
diff --git a/src/calibre/scraper/simple.py b/src/calibre/scraper/simple.py
index bef2a36d36..a150d5c26a 100644
--- a/src/calibre/scraper/simple.py
+++ b/src/calibre/scraper/simple.py
@@ -139,6 +139,7 @@ def read_url(storage, url, timeout=60):
 def find_tests():
     import re
     import unittest
+
     from lxml.html import fromstring, tostring
     skip = ''
     is_sanitized = 'libasan' in os.environ.get('LD_PRELOAD', '')
diff --git a/src/calibre/scraper/simple_backend.py b/src/calibre/scraper/simple_backend.py
index 1338f922bb..46570d78be 100644
--- a/src/calibre/scraper/simple_backend.py
+++ b/src/calibre/scraper/simple_backend.py
@@ -6,6 +6,7 @@ import secrets
 import sys
 import time
 from functools import lru_cache
+
 from qt.core import QApplication, QEventLoop, QUrl
 from qt.webengine import QWebEnginePage, QWebEngineProfile, QWebEngineSettings
 
diff --git a/src/calibre/spell/dictionary.py b/src/calibre/spell/dictionary.py
index 434d877d6a..7e1ecad0c4 100644
--- a/src/calibre/spell/dictionary.py
+++ b/src/calibre/spell/dictionary.py
@@ -3,11 +3,11 @@
 
 
 import glob
+import json
 import os
 import re
 import shutil
 import sys
-import json
 from collections import defaultdict, namedtuple
 from functools import partial
 from itertools import chain
diff --git a/src/calibre/spell/import_from.py b/src/calibre/spell/import_from.py
index ff425461a2..ef6fd54895 100644
--- a/src/calibre/spell/import_from.py
+++ b/src/calibre/spell/import_from.py
@@ -4,15 +4,20 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import sys, glob, os, tempfile, re, codecs
+import codecs
+import glob
+import os
+import re
+import sys
+import tempfile
 
 from lxml import etree
 
 from calibre import browser
 from calibre.constants import config_dir
+from calibre.utils.resources import get_path as P
 from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.utils.zipfile import ZipFile
-from calibre.utils.resources import get_path as P
 from polyglot.builtins import iteritems
 
 NS_MAP = {
diff --git a/src/calibre/srv/ajax.py b/src/calibre/srv/ajax.py
index 6fa95acab4..24c4049c27 100644
--- a/src/calibre/srv/ajax.py
+++ b/src/calibre/srv/ajax.py
@@ -12,12 +12,11 @@ from calibre.db.view import sanitize_sort_field_name
 from calibre.ebooks.metadata import title_sort
 from calibre.ebooks.metadata.book.json_codec import JsonCodec
 from calibre.library.field_metadata import category_icon_map
-from calibre.srv.content import get as get_content, icon as get_icon
+from calibre.srv.content import get as get_content
+from calibre.srv.content import icon as get_icon
 from calibre.srv.errors import BookNotFound, HTTPNotFound
 from calibre.srv.routes import endpoint, json
-from calibre.srv.utils import (
-    custom_fields_to_display, decode_name, encode_name, get_db, http_date,
-)
+from calibre.srv.utils import custom_fields_to_display, decode_name, encode_name, get_db, http_date
 from calibre.utils.config import prefs, tweaks
 from calibre.utils.date import isoformat, timestampfromdt
 from calibre.utils.icu import numeric_sort_key as sort_key
diff --git a/src/calibre/srv/auth.py b/src/calibre/srv/auth.py
index 8396316937..34b89b56d9 100644
--- a/src/calibre/srv/auth.py
+++ b/src/calibre/srv/auth.py
@@ -4,18 +4,20 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, random, struct
+import os
+import random
+import struct
 from collections import OrderedDict
 from hashlib import md5, sha256
 from itertools import permutations
 from threading import Lock
 
-from calibre.srv.errors import HTTPAuthRequired, HTTPSimpleResponse, HTTPForbidden
+from calibre.srv.errors import HTTPAuthRequired, HTTPForbidden, HTTPSimpleResponse
 from calibre.srv.http_request import parse_uri
-from calibre.srv.utils import parse_http_dict, encode_path
+from calibre.srv.utils import encode_path, parse_http_dict
 from calibre.utils.monotonic import monotonic
 from polyglot import http_client
-from polyglot.binary import from_base64_unicode, from_hex_bytes, as_hex_unicode
+from polyglot.binary import as_hex_unicode, from_base64_unicode, from_hex_bytes
 
 MAX_AGE_SECONDS = 3600
 nonce_counter, nonce_counter_lock = 0, Lock()
diff --git a/src/calibre/srv/code.py b/src/calibre/srv/code.py
index 70435e64db..9e75063dcd 100644
--- a/src/calibre/srv/code.py
+++ b/src/calibre/srv/code.py
@@ -7,7 +7,8 @@ import random
 import shutil
 import sys
 import zipfile
-from json import load as load_json_file, loads as json_loads
+from json import load as load_json_file
+from json import loads as json_loads
 from threading import Lock
 
 from calibre import as_unicode
@@ -15,20 +16,14 @@ from calibre.constants import in_develop_mode
 from calibre.customize.ui import available_input_formats
 from calibre.db.view import sanitize_sort_field_name
 from calibre.srv.ajax import search_result
-from calibre.srv.errors import (
-    BookNotFound, HTTPBadRequest, HTTPForbidden, HTTPNotFound, HTTPRedirect,
-)
+from calibre.srv.errors import BookNotFound, HTTPBadRequest, HTTPForbidden, HTTPNotFound, HTTPRedirect
 from calibre.srv.last_read import last_read_cache
-from calibre.srv.metadata import (
-    book_as_json, categories_as_json, categories_settings, icon_map,
-)
+from calibre.srv.metadata import book_as_json, categories_as_json, categories_settings, icon_map
 from calibre.srv.routes import endpoint, json
 from calibre.srv.utils import get_library_data, get_use_roman
 from calibre.utils.config import prefs, tweaks
 from calibre.utils.icu import numeric_sort_key, sort_key
-from calibre.utils.localization import (
-    _, get_lang, lang_code_for_user_manual, lang_map_for_ui, localize_website_link,
-)
+from calibre.utils.localization import _, get_lang, lang_code_for_user_manual, lang_map_for_ui, localize_website_link
 from calibre.utils.resources import get_path as P
 from calibre.utils.search_query_parser import ParseException
 from calibre.utils.serialize import json_dumps
diff --git a/src/calibre/srv/content.py b/src/calibre/srv/content.py
index 77346c9879..f1c723e65a 100644
--- a/src/calibre/srv/content.py
+++ b/src/calibre/srv/content.py
@@ -18,9 +18,7 @@ from calibre import fit_image, guess_type, sanitize_file_name
 from calibre.constants import config_dir, iswindows
 from calibre.db.constants import RESOURCE_URL_SCHEME
 from calibre.db.errors import NoSuchFormat
-from calibre.ebooks.covers import (
-    cprefs, generate_cover, override_prefs, scale_cover, set_use_roman,
-)
+from calibre.ebooks.covers import cprefs, generate_cover, override_prefs, scale_cover, set_use_roman
 from calibre.ebooks.metadata import authors_to_string
 from calibre.ebooks.metadata.meta import set_metadata
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
@@ -30,12 +28,11 @@ from calibre.srv.routes import endpoint, json
 from calibre.srv.utils import get_db, get_use_roman, http_date
 from calibre.utils.config_base import tweaks
 from calibre.utils.date import timestampfromdt
-from calibre.utils.filenames import (
-    ascii_filename, atomic_rename, make_long_path_useable,
-)
+from calibre.utils.filenames import ascii_filename, atomic_rename, make_long_path_useable
 from calibre.utils.img import image_from_data, scale_image
 from calibre.utils.localization import _
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from calibre.utils.shared_file import share_open
 from polyglot.binary import as_hex_unicode
 from polyglot.urllib import quote
diff --git a/src/calibre/srv/convert.py b/src/calibre/srv/convert.py
index 7741913d9b..5fed175b28 100644
--- a/src/calibre/srv/convert.py
+++ b/src/calibre/srv/convert.py
@@ -205,10 +205,7 @@ def conversion_status(ctx, rd, job_id):
 
 def get_conversion_options(input_fmt, output_fmt, book_id, db):
     from calibre.customize.conversion import OptionRecommendation
-    from calibre.ebooks.conversion.config import (
-        OPTIONS, load_defaults, load_specifics, options_for_input_fmt,
-        options_for_output_fmt,
-    )
+    from calibre.ebooks.conversion.config import OPTIONS, load_defaults, load_specifics, options_for_input_fmt, options_for_output_fmt
     from calibre.ebooks.conversion.plumber import create_dummy_plumber
     plumber = create_dummy_plumber(input_fmt, output_fmt)
     specifics = load_specifics(db, book_id)
@@ -268,9 +265,7 @@ def profiles():
 
 @endpoint('/conversion/book-data/{book_id}', postprocess=json, types={'book_id': int})
 def conversion_data(ctx, rd, book_id):
-    from calibre.ebooks.conversion.config import (
-        NoSupportedInputFormats, get_input_format_for_book, get_sorted_output_formats,
-    )
+    from calibre.ebooks.conversion.config import NoSupportedInputFormats, get_input_format_for_book, get_sorted_output_formats
     db = get_library_data(ctx, rd)[0]
     if not ctx.has_id(rd, db, book_id):
         raise BookNotFound(book_id, db)
diff --git a/src/calibre/srv/fts.py b/src/calibre/srv/fts.py
index 1c14dd445c..cc4cae42fa 100644
--- a/src/calibre/srv/fts.py
+++ b/src/calibre/srv/fts.py
@@ -4,9 +4,7 @@
 import re
 
 from calibre.ebooks.metadata import authors_to_string
-from calibre.srv.errors import (
-    HTTPBadRequest, HTTPPreconditionRequired, HTTPUnprocessableEntity,
-)
+from calibre.srv.errors import HTTPBadRequest, HTTPPreconditionRequired, HTTPUnprocessableEntity
 from calibre.srv.routes import endpoint, json
 from calibre.srv.utils import get_library_data
 
diff --git a/src/calibre/srv/http_request.py b/src/calibre/srv/http_request.py
index 8f7320f3c3..29ef335f97 100644
--- a/src/calibre/srv/http_request.py
+++ b/src/calibre/srv/http_request.py
@@ -5,16 +5,16 @@ __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
-from io import BytesIO, DEFAULT_BUFFER_SIZE
+from io import DEFAULT_BUFFER_SIZE, BytesIO
 
 from calibre import as_unicode, force_unicode
 from calibre.ptempfile import SpooledTemporaryFile
 from calibre.srv.errors import HTTPSimpleResponse
-from calibre.srv.loop import Connection, READ, WRITE
-from calibre.srv.utils import MultiDict, HTTP1, HTTP11, Accumulator
+from calibre.srv.loop import READ, WRITE, Connection
+from calibre.srv.utils import HTTP1, HTTP11, Accumulator, MultiDict
 from polyglot import http_client, reprlib
-from polyglot.urllib import unquote
 from polyglot.builtins import error_message
+from polyglot.urllib import unquote
 
 protocol_map = {(1, 0):HTTP1, (1, 1):HTTP11}
 quoted_slash = re.compile(br'%2[fF]')
diff --git a/src/calibre/srv/http_response.py b/src/calibre/srv/http_response.py
index d8cbf1a4e4..e151c82999 100644
--- a/src/calibre/srv/http_response.py
+++ b/src/calibre/srv/http_response.py
@@ -21,16 +21,11 @@ from calibre.constants import __version__
 from calibre.srv.errors import HTTPSimpleResponse
 from calibre.srv.http_request import HTTPRequest, read_headers
 from calibre.srv.loop import WRITE
-from calibre.srv.utils import (
-    HTTP1, HTTP11, Cookie, MultiDict, get_translator_for_lang,
-    http_date, socket_errors_socket_closed, sort_q_values
-)
+from calibre.srv.utils import HTTP1, HTTP11, Cookie, MultiDict, get_translator_for_lang, http_date, socket_errors_socket_closed, sort_q_values
 from calibre.utils.monotonic import monotonic
 from calibre.utils.speedups import ReadOnlyFileBuffer
 from polyglot import http_client, reprlib
-from polyglot.builtins import (
-    error_message, iteritems, itervalues, reraise, string_or_bytes
-)
+from polyglot.builtins import error_message, iteritems, itervalues, reraise, string_or_bytes
 
 Range = namedtuple('Range', 'start stop size')
 MULTIPART_SEPARATOR = uuid.uuid4().hex
diff --git a/src/calibre/srv/jobs.py b/src/calibre/srv/jobs.py
index 79f1cab431..29f6416615 100644
--- a/src/calibre/srv/jobs.py
+++ b/src/calibre/srv/jobs.py
@@ -2,17 +2,18 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import os, time
-from itertools import count
-from collections import namedtuple, deque
+import os
+import time
+from collections import deque, namedtuple
 from functools import partial
-from threading import RLock, Thread, Event
+from itertools import count
+from threading import Event, RLock, Thread
 
 from calibre import detect_ncpus, force_unicode
+from calibre.utils.ipc.simple_worker import WorkerError, fork_job
 from calibre.utils.monotonic import monotonic
-from calibre.utils.ipc.simple_worker import fork_job, WorkerError
-from polyglot.queue import Queue, Empty
 from polyglot.builtins import iteritems, itervalues
+from polyglot.queue import Empty, Queue
 
 StartEvent = namedtuple('StartEvent', 'job_id name module function args kwargs callback data')
 DoneEvent = namedtuple('DoneEvent', 'job_id')
diff --git a/src/calibre/srv/last_read.py b/src/calibre/srv/last_read.py
index 7215c39fee..f6fc609ebe 100644
--- a/src/calibre/srv/last_read.py
+++ b/src/calibre/srv/last_read.py
@@ -1,12 +1,13 @@
 #!/usr/bin/env python
 # License: GPL v3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
 
-import apsw
 import os
 from contextlib import suppress
 from threading import Lock
 from time import time_ns
 
+import apsw
+
 from calibre.constants import cache_dir
 
 creation_sql = '''
diff --git a/src/calibre/srv/legacy.py b/src/calibre/srv/legacy.py
index fa54504587..d05fb696a5 100644
--- a/src/calibre/srv/legacy.py
+++ b/src/calibre/srv/legacy.py
@@ -3,6 +3,7 @@
 
 
 from functools import partial
+
 from lxml.html import tostring
 from lxml.html.builder import E as E_
 
diff --git a/src/calibre/srv/loop.py b/src/calibre/srv/loop.py
index 531fc53602..d6b47a2325 100644
--- a/src/calibre/srv/loop.py
+++ b/src/calibre/srv/loop.py
@@ -23,8 +23,14 @@ from calibre.srv.jobs import JobsManager
 from calibre.srv.opts import Options
 from calibre.srv.pool import PluginPool, ThreadPool
 from calibre.srv.utils import (
-    DESIRED_SEND_BUFFER_SIZE, HandleInterrupt, create_sock_pair, socket_errors_eintr,
-    socket_errors_nonblocking, socket_errors_socket_closed, start_cork, stop_cork,
+    DESIRED_SEND_BUFFER_SIZE,
+    HandleInterrupt,
+    create_sock_pair,
+    socket_errors_eintr,
+    socket_errors_nonblocking,
+    socket_errors_socket_closed,
+    start_cork,
+    stop_cork,
 )
 from calibre.utils.localization import _
 from calibre.utils.logging import ThreadSafeLog
diff --git a/src/calibre/srv/metadata.py b/src/calibre/srv/metadata.py
index d600b909e5..7a4d74defa 100644
--- a/src/calibre/srv/metadata.py
+++ b/src/calibre/srv/metadata.py
@@ -18,7 +18,8 @@ from calibre.utils.config import tweaks
 from calibre.utils.date import UNDEFINED_DATE, isoformat, local_tz
 from calibre.utils.file_type_icons import EXT_MAP
 from calibre.utils.formatter import EvalFormatter
-from calibre.utils.icu import collation_order_for_partitioning, upper as icu_upper
+from calibre.utils.icu import collation_order_for_partitioning
+from calibre.utils.icu import upper as icu_upper
 from calibre.utils.localization import _, calibre_langcode_to_name
 from polyglot.builtins import iteritems, itervalues
 from polyglot.urllib import quote
diff --git a/src/calibre/srv/opds.py b/src/calibre/srv/opds.py
index 0dd6ab8eb3..93ec02c297 100644
--- a/src/calibre/srv/opds.py
+++ b/src/calibre/srv/opds.py
@@ -8,11 +8,13 @@ __docformat__ = 'restructuredtext en'
 import hashlib
 from collections import OrderedDict, namedtuple
 from functools import partial
+
 from html5_parser import parse
 from lxml import etree
 from lxml.builder import ElementMaker
 
-from calibre import force_unicode, guess_type, prepare_string_for_xml as xml
+from calibre import force_unicode, guess_type
+from calibre import prepare_string_for_xml as xml
 from calibre.constants import __appname__
 from calibre.db.view import sanitize_sort_field_name
 from calibre.ebooks.metadata import authors_to_string, fmt_sidx, rating_to_stars
diff --git a/src/calibre/srv/pool.py b/src/calibre/srv/pool.py
index 72fc3ac34d..e1caa505c7 100644
--- a/src/calibre/srv/pool.py
+++ b/src/calibre/srv/pool.py
@@ -8,7 +8,7 @@ import sys
 from threading import Thread
 
 from calibre.utils.monotonic import monotonic
-from polyglot.queue import Queue, Full
+from polyglot.queue import Full, Queue
 
 
 class Worker(Thread):
diff --git a/src/calibre/srv/pre_activated.py b/src/calibre/srv/pre_activated.py
index ff34f2cee3..db8eb657b3 100644
--- a/src/calibre/srv/pre_activated.py
+++ b/src/calibre/srv/pre_activated.py
@@ -6,7 +6,9 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 # Support server pre-activation, such as with systemd's socket activation
 
-import socket, errno
+import errno
+import socket
+
 from calibre.constants import islinux
 
 
diff --git a/src/calibre/srv/render_book.py b/src/calibre/srv/render_book.py
index 6a2e97c8ab..bce7fb7ac4 100644
--- a/src/calibre/srv/render_book.py
+++ b/src/calibre/srv/render_book.py
@@ -11,21 +11,18 @@ from collections import defaultdict
 from datetime import datetime
 from functools import partial
 from itertools import count
-from lxml.etree import Comment
 from math import ceil
 
+from lxml.etree import Comment
+
 from calibre import detect_ncpus, force_unicode, prepare_string_for_xml
 from calibre.constants import iswindows
 from calibre.customize.ui import plugin_for_input_format
-from calibre.ebooks.oeb.base import (
-    EPUB, OEB_DOCS, OEB_STYLES, OPF, SMIL, XHTML, XHTML_NS, XLINK, XPath as _XPath,
-    rewrite_links, urlunquote,
-)
+from calibre.ebooks.oeb.base import EPUB, OEB_DOCS, OEB_STYLES, OPF, SMIL, XHTML, XHTML_NS, XLINK, rewrite_links, urlunquote
+from calibre.ebooks.oeb.base import XPath as _XPath
 from calibre.ebooks.oeb.iterator.book import extract_book
 from calibre.ebooks.oeb.polish.container import Container as ContainerBase
-from calibre.ebooks.oeb.polish.cover import (
-    find_cover_image, find_cover_image_in_page, find_cover_page,
-)
+from calibre.ebooks.oeb.polish.cover import find_cover_image, find_cover_image_in_page, find_cover_page
 from calibre.ebooks.oeb.polish.toc import from_xpaths, get_landmarks, get_toc
 from calibre.ebooks.oeb.polish.utils import guess_type
 from calibre.ptempfile import PersistentTemporaryDirectory
@@ -39,10 +36,9 @@ from calibre.utils.serialize import json_dumps, json_loads, msgpack_dumps, msgpa
 from calibre.utils.short_uuid import uuid4
 from calibre_extensions import speedup
 from calibre_extensions.fast_css_transform import transform_properties
-from polyglot.binary import (
-    as_base64_unicode as encode_component, from_base64_bytes,
-    from_base64_unicode as decode_component,
-)
+from polyglot.binary import as_base64_unicode as encode_component
+from polyglot.binary import from_base64_bytes
+from polyglot.binary import from_base64_unicode as decode_component
 from polyglot.builtins import as_bytes, iteritems
 from polyglot.urllib import quote, urlparse
 
diff --git a/src/calibre/srv/routes.py b/src/calibre/srv/routes.py
index 7c39a523fe..c07d37b9bf 100644
--- a/src/calibre/srv/routes.py
+++ b/src/calibre/srv/routes.py
@@ -4,14 +4,20 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import sys, inspect, re, time, numbers, json as jsonlib, textwrap
+import inspect
+import json as jsonlib
+import numbers
+import re
+import sys
+import textwrap
+import time
 from operator import attrgetter
 
-from calibre.srv.errors import HTTPSimpleResponse, HTTPNotFound, RouteError
+from calibre.srv.errors import HTTPNotFound, HTTPSimpleResponse, RouteError
 from calibre.srv.utils import http_date
-from calibre.utils.serialize import msgpack_dumps, json_dumps, MSGPACK_MIME
-from polyglot.builtins import iteritems, itervalues
+from calibre.utils.serialize import MSGPACK_MIME, json_dumps, msgpack_dumps
 from polyglot import http_client
+from polyglot.builtins import iteritems, itervalues
 from polyglot.urllib import quote as urlquote
 
 default_methods = frozenset(('HEAD', 'GET'))
diff --git a/src/calibre/srv/tests/auth.py b/src/calibre/srv/tests/auth.py
index 94fd56b8e4..09d8fa8714 100644
--- a/src/calibre/srv/tests/auth.py
+++ b/src/calibre/srv/tests/auth.py
@@ -4,19 +4,21 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import subprocess, os, time, shutil
+import os
+import shutil
+import subprocess
+import time
 from collections import namedtuple
 
 from calibre.ptempfile import TemporaryDirectory
 from calibre.srv.errors import HTTPForbidden
+from calibre.srv.routes import Router, endpoint
 from calibre.srv.tests.base import BaseTest, TestServer
-from calibre.srv.routes import endpoint, Router
-from polyglot.builtins import iteritems, itervalues
 from polyglot import http_client
-from polyglot.http_cookie import CookieJar
-from polyglot.urllib import (build_opener, HTTPBasicAuthHandler,
-        HTTPCookieProcessor, HTTPDigestAuthHandler, HTTPError)
 from polyglot.binary import as_base64_bytes
+from polyglot.builtins import iteritems, itervalues
+from polyglot.http_cookie import CookieJar
+from polyglot.urllib import HTTPBasicAuthHandler, HTTPCookieProcessor, HTTPDigestAuthHandler, HTTPError, build_opener
 
 REALM = 'calibre-test'
 
@@ -121,9 +123,9 @@ class TestAuth(BaseTest):
     # }}}
 
     def test_library_restrictions(self):  # {{{
-        from calibre.srv.opts import Options
-        from calibre.srv.handler import Handler
         from calibre.db.legacy import create_backend
+        from calibre.srv.handler import Handler
+        from calibre.srv.opts import Options
         opts = Options(userdb=':memory:')
         Data = namedtuple('Data', 'username')
         with TemporaryDirectory() as base:
diff --git a/src/calibre/srv/tests/base.py b/src/calibre/srv/tests/base.py
index cf2ce9cd04..fc9fa2edd8 100644
--- a/src/calibre/srv/tests/base.py
+++ b/src/calibre/srv/tests/base.py
@@ -17,7 +17,8 @@ from io import BytesIO
 from threading import Thread
 
 from calibre.srv.utils import ServerLog
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from polyglot import http_client
 
 rmtree = partial(shutil.rmtree, ignore_errors=True)
diff --git a/src/calibre/srv/tests/content.py b/src/calibre/srv/tests/content.py
index da8c183bff..a045a34009 100644
--- a/src/calibre/srv/tests/content.py
+++ b/src/calibre/srv/tests/content.py
@@ -14,7 +14,8 @@ from calibre.ebooks.metadata.epub import get_metadata
 from calibre.ebooks.metadata.opf2 import OPF
 from calibre.srv.tests.base import LibraryBaseTest
 from calibre.utils.imghdr import identify
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from calibre.utils.shared_file import share_open
 from polyglot import http_client
 from polyglot.binary import from_hex_unicode
diff --git a/src/calibre/srv/tests/loop.py b/src/calibre/srv/tests/loop.py
index a5f3bccc01..7e4ea0e857 100644
--- a/src/calibre/srv/tests/loop.py
+++ b/src/calibre/srv/tests/loop.py
@@ -4,18 +4,22 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import ssl, os, socket, time
+import os
+import socket
+import ssl
+import time
 from collections import namedtuple
-from unittest import skipIf
 from glob import glob
 from threading import Event
+from unittest import skipIf
 
+from calibre.ptempfile import TemporaryDirectory
 from calibre.srv.pre_activated import has_preactivated_support
 from calibre.srv.tests.base import BaseTest, TestServer
-from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.certgen import create_server_cert
 from calibre.utils.monotonic import monotonic
 from polyglot import http_client
+
 is_ci = os.environ.get('CI', '').lower() == 'true'
 
 
@@ -23,8 +27,8 @@ class LoopTest(BaseTest):
 
     def test_log_rotation(self):
         'Test log rotation'
-        from calibre.srv.utils import RotatingLog
         from calibre.ptempfile import TemporaryDirectory
+        from calibre.srv.utils import RotatingLog
         with TemporaryDirectory() as tdir:
             fname = os.path.join(tdir, 'log')
             l = RotatingLog(fname, max_size=100)
@@ -106,8 +110,9 @@ class LoopTest(BaseTest):
     @skipIf(True, 'Disabled as it is failing on the build server, need to investigate')
     def test_bonjour(self):
         'Test advertising via BonJour'
-        from calibre.srv.bonjour import BonJour
         from zeroconf import Zeroconf
+
+        from calibre.srv.bonjour import BonJour
         b = BonJour(wait_for_stop=False)
         with TestServer(lambda data:(data.path[0] + data.read()), plugins=(b,), shutdown_timeout=5) as server:
             self.assertTrue(b.started.wait(5), 'BonJour not started')
@@ -143,7 +148,7 @@ class LoopTest(BaseTest):
                 sz = min(len(mv), len(self.data))
                 mv[:sz] = self.data[:sz]
                 return sz
-        from calibre.srv.loop import ReadBuffer, READ, WRITE
+        from calibre.srv.loop import READ, WRITE, ReadBuffer
         buf = ReadBuffer(100)
 
         def write(data):
diff --git a/src/calibre/srv/tests/routes.py b/src/calibre/srv/tests/routes.py
index edf1955af8..8371ca8da7 100644
--- a/src/calibre/srv/tests/routes.py
+++ b/src/calibre/srv/tests/routes.py
@@ -5,15 +5,16 @@ __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
+from tempfile import TemporaryDirectory
+
 from calibre.srv.tests.base import BaseTest
 from polyglot.builtins import itervalues
-from tempfile import TemporaryDirectory
 
 
 class TestRouter(BaseTest):
 
     def test_library_id_construction(self):
-        from calibre.srv.library_broker import library_id_from_path, correct_case_of_last_path_component, db_matches
+        from calibre.srv.library_broker import correct_case_of_last_path_component, db_matches, library_id_from_path
         self.ae(library_id_from_path('as'), 'as')
         self.ae(library_id_from_path('as/'), 'as')
         self.ae(library_id_from_path('as////'), 'as')
@@ -40,7 +41,7 @@ class TestRouter(BaseTest):
 
     def test_route_construction(self):
         ' Test route construction '
-        from calibre.srv.routes import Route, endpoint, RouteError
+        from calibre.srv.routes import Route, RouteError, endpoint
 
         def makeroute(route, func=lambda c,d:None, **kwargs):
             return Route(endpoint(route, **kwargs)(func))
@@ -64,7 +65,7 @@ class TestRouter(BaseTest):
 
     def test_route_finding(self):
         'Test route finding'
-        from calibre.srv.routes import Router, endpoint, HTTPNotFound
+        from calibre.srv.routes import HTTPNotFound, Router, endpoint
         router = Router()
 
         def find(path):
diff --git a/src/calibre/srv/tests/web_sockets.py b/src/calibre/srv/tests/web_sockets.py
index 56bfe9ad0e..6c31ca566c 100644
--- a/src/calibre/srv/tests/web_sockets.py
+++ b/src/calibre/srv/tests/web_sockets.py
@@ -2,15 +2,31 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import socket, os, struct, errno, numbers
+import errno
+import numbers
+import os
+import socket
+import struct
 from collections import deque, namedtuple
 from functools import partial
 from hashlib import sha1
 
 from calibre.srv.tests.base import BaseTest, TestServer
 from calibre.srv.web_socket import (
-    GUID_STR, BINARY, TEXT, MessageWriter, create_frame, CLOSE, NORMAL_CLOSE,
-    PING, PONG, PROTOCOL_ERROR, CONTINUATION, INCONSISTENT_DATA, CONTROL_CODES)
+    BINARY,
+    CLOSE,
+    CONTINUATION,
+    CONTROL_CODES,
+    GUID_STR,
+    INCONSISTENT_DATA,
+    NORMAL_CLOSE,
+    PING,
+    PONG,
+    PROTOCOL_ERROR,
+    TEXT,
+    MessageWriter,
+    create_frame,
+)
 from calibre.utils.monotonic import monotonic
 from calibre.utils.socket_inheritance import set_socket_inherit
 from polyglot.binary import as_base64_unicode
diff --git a/src/calibre/srv/users.py b/src/calibre/srv/users.py
index 3b26d96921..3a5f00e1b1 100644
--- a/src/calibre/srv/users.py
+++ b/src/calibre/srv/users.py
@@ -2,13 +2,14 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import apsw
 import json
 import os
 import re
 from functools import lru_cache
 from threading import RLock
 
+import apsw
+
 from calibre import as_unicode
 from calibre.constants import config_dir
 from calibre.utils.config import from_json, to_json
diff --git a/src/calibre/srv/utils.py b/src/calibre/srv/utils.py
index b4c5ee84bb..2925e7fa30 100644
--- a/src/calibre/srv/utils.py
+++ b/src/calibre/srv/utils.py
@@ -4,7 +4,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import errno, socket, os
+import errno
+import os
+import socket
 from email.utils import formatdate
 from operator import itemgetter
 
@@ -12,15 +14,16 @@ from calibre import prints
 from calibre.constants import iswindows
 from calibre.srv.errors import HTTPNotFound
 from calibre.utils.localization import get_translator
-from calibre.utils.socket_inheritance import set_socket_inherit
 from calibre.utils.logging import ThreadSafeLog
 from calibre.utils.shared_file import share_open
-from polyglot.builtins import iteritems
+from calibre.utils.socket_inheritance import set_socket_inherit
 from polyglot import reprlib
+from polyglot.binary import as_hex_unicode as encode_name
+from polyglot.binary import from_hex_unicode as decode_name
+from polyglot.builtins import as_unicode, iteritems
 from polyglot.http_cookie import SimpleCookie
-from polyglot.builtins import as_unicode
-from polyglot.urllib import parse_qs, quote as urlquote
-from polyglot.binary import as_hex_unicode as encode_name, from_hex_unicode as decode_name
+from polyglot.urllib import parse_qs
+from polyglot.urllib import quote as urlquote
 
 HTTP1  = 'HTTP/1.0'
 HTTP11 = 'HTTP/1.1'
diff --git a/src/calibre/srv/web_socket.py b/src/calibre/srv/web_socket.py
index aeb2172220..4ba685b290 100644
--- a/src/calibre/srv/web_socket.py
+++ b/src/calibre/srv/web_socket.py
@@ -5,19 +5,19 @@
 import os
 import socket
 import weakref
-from calibre_extensions.speedup import utf8_decode, websocket_mask as fast_mask
 from collections import deque
 from hashlib import sha1
-from struct import error as struct_error, pack, unpack_from
+from struct import error as struct_error
+from struct import pack, unpack_from
 from threading import Lock
 
 from calibre import as_unicode
 from calibre.srv.http_response import HTTPConnection, create_http_handler
-from calibre.srv.loop import (
-    RDWR, READ, WRITE, Connection, HandleInterrupt, ServerLoop
-)
+from calibre.srv.loop import RDWR, READ, WRITE, Connection, HandleInterrupt, ServerLoop
 from calibre.srv.utils import DESIRED_SEND_BUFFER_SIZE
 from calibre.utils.speedups import ReadOnlyFileBuffer
+from calibre_extensions.speedup import utf8_decode
+from calibre_extensions.speedup import websocket_mask as fast_mask
 from polyglot import http_client
 from polyglot.binary import as_base64_unicode
 from polyglot.queue import Empty, Queue
diff --git a/src/calibre/startup.py b/src/calibre/startup.py
index 32ade5037c..64474f751b 100644
--- a/src/calibre/startup.py
+++ b/src/calibre/startup.py
@@ -153,7 +153,9 @@ def initialize_calibre():
             pass
 
     builtins.__dict__['lopen'] = open  # legacy compatibility
-    from calibre.utils.icu import lower as icu_lower, title_case, upper as icu_upper
+    from calibre.utils.icu import lower as icu_lower
+    from calibre.utils.icu import title_case
+    from calibre.utils.icu import upper as icu_upper
     builtins.__dict__['icu_lower'] = icu_lower
     builtins.__dict__['icu_upper'] = icu_upper
     builtins.__dict__['icu_title'] = title_case
diff --git a/src/calibre/test_build.py b/src/calibre/test_build.py
index 4d4c23a32e..53c8de0ed2 100644
--- a/src/calibre/test_build.py
+++ b/src/calibre/test_build.py
@@ -18,7 +18,8 @@ import time
 import unittest
 
 from calibre.constants import islinux, ismacos, iswindows, plugins_loc
-from calibre.utils.resources import get_image_path as I, get_path as P
+from calibre.utils.resources import get_image_path as I
+from calibre.utils.resources import get_path as P
 from polyglot.builtins import iteritems
 
 is_ci = os.environ.get('CI', '').lower() == 'true'
@@ -313,10 +314,7 @@ class BuildTest(unittest.TestCase):
     def test_qt(self):
         if is_sanitized:
             raise unittest.SkipTest('Skipping Qt build test as sanitizer is enabled')
-        from qt.core import (
-            QApplication, QFontDatabase, QImageReader, QLoggingCategory,
-            QNetworkAccessManager, QSslSocket, QTimer,
-        )
+        from qt.core import QApplication, QFontDatabase, QImageReader, QLoggingCategory, QNetworkAccessManager, QSslSocket, QTimer
         QLoggingCategory.setFilterRules('''qt.webenginecontext.debug=true''')
         from qt.webengine import QWebEnginePage
 
@@ -407,6 +405,7 @@ class BuildTest(unittest.TestCase):
             from PIL import _imaging, _imagingft, _imagingmath
         _imaging, _imagingmath, _imagingft
         from io import StringIO
+
         from PIL import features
         out = StringIO()
         features.pilinfo(out=out, supported_formats=False)
diff --git a/src/calibre/translations/dynamic.py b/src/calibre/translations/dynamic.py
index 5ad04e3cd0..1839c43322 100644
--- a/src/calibre/translations/dynamic.py
+++ b/src/calibre/translations/dynamic.py
@@ -7,9 +7,10 @@ __copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
 
 import io
 from gettext import GNUTranslations
+from zipfile import ZipFile
+
 from calibre.utils.localization import get_lc_messages_path
 from calibre.utils.resources import get_path
-from zipfile import ZipFile
 
 __all__ = ['translate']
 
diff --git a/src/calibre/translations/msgfmt.py b/src/calibre/translations/msgfmt.py
index 0f0571bc90..225d47ef85 100644
--- a/src/calibre/translations/msgfmt.py
+++ b/src/calibre/translations/msgfmt.py
@@ -26,12 +26,12 @@ Options:
         Display version information and exit.
 """
 
-import os
-import sys
+import array
 import ast
 import getopt
+import os
 import struct
-import array
+import sys
 from email.parser import HeaderParser
 
 __version__ = "1.2"
diff --git a/src/calibre/utils/__init__.py b/src/calibre/utils/__init__.py
index bbca860b44..abe02a043e 100644
--- a/src/calibre/utils/__init__.py
+++ b/src/calibre/utils/__init__.py
@@ -10,6 +10,7 @@ Miscelleaneous utilities.
 '''
 
 from time import time
+
 from polyglot.builtins import as_bytes
 
 
diff --git a/src/calibre/utils/bibtex.py b/src/calibre/utils/bibtex.py
index 7784b07fd4..77c8ea573b 100644
--- a/src/calibre/utils/bibtex.py
+++ b/src/calibre/utils/bibtex.py
@@ -63,7 +63,8 @@
 __author__  = 'sengian <sengian1 at gmail.com>'
 __docformat__ = 'restructuredtext en'
 
-import re, string
+import re
+import string
 
 from calibre.utils.mreplace import MReplace
 
diff --git a/src/calibre/utils/browser.py b/src/calibre/utils/browser.py
index fdb109132f..d416ebbb29 100644
--- a/src/calibre/utils/browser.py
+++ b/src/calibre/utils/browser.py
@@ -5,7 +5,8 @@
 import copy
 import ssl
 
-from mechanize import Browser as B, HTTPSHandler
+from mechanize import Browser as B
+from mechanize import HTTPSHandler
 
 from polyglot import http_client
 from polyglot.http_cookie import CookieJar
@@ -153,8 +154,9 @@ class Browser(B):
 
 
 if __name__ == '__main__':
-    from calibre import browser
     from pprint import pprint
+
+    from calibre import browser
     orig = browser()
     clone = orig.clone_browser()
     pprint(orig._ua_handlers)
diff --git a/src/calibre/utils/certgen.py b/src/calibre/utils/certgen.py
index 55f2e4ec6a..68524a292c 100644
--- a/src/calibre/utils/certgen.py
+++ b/src/calibre/utils/certgen.py
@@ -5,6 +5,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import socket
+
 from calibre_extensions import certgen
 
 
diff --git a/src/calibre/utils/complete.py b/src/calibre/utils/complete.py
index 2eb9e3d96f..38387a7ade 100644
--- a/src/calibre/utils/complete.py
+++ b/src/calibre/utils/complete.py
@@ -11,8 +11,11 @@ BASH completion for calibre commands that are too complex for simple
 completion.
 '''
 
-import sys, os, shlex, glob, re
-
+import glob
+import os
+import re
+import shlex
+import sys
 
 prints = print
 
diff --git a/src/calibre/utils/config.py b/src/calibre/utils/config.py
index dc2ac2e1ba..b306b66513 100644
--- a/src/calibre/utils/config.py
+++ b/src/calibre/utils/config.py
@@ -10,13 +10,25 @@ import optparse
 import os
 from copy import deepcopy
 
-from calibre.constants import (
-    CONFIG_DIR_MODE, __appname__, __author__, config_dir, get_version, iswindows,
-)
+from calibre.constants import CONFIG_DIR_MODE, __appname__, __author__, config_dir, get_version, iswindows
 from calibre.utils.config_base import (
-    Config, ConfigInterface, ConfigProxy, Option, OptionSet, OptionValues, StringConfig,
-    commit_data, from_json, json_dumps, json_loads, make_config_dir, plugin_dir, prefs,
-    read_data, to_json, tweaks,
+    Config,
+    ConfigInterface,
+    ConfigProxy,
+    Option,
+    OptionSet,
+    OptionValues,
+    StringConfig,
+    commit_data,
+    from_json,
+    json_dumps,
+    json_loads,
+    make_config_dir,
+    plugin_dir,
+    prefs,
+    read_data,
+    to_json,
+    tweaks,
 )
 from calibre.utils.localization import _
 from polyglot.builtins import native_string_type, string_or_bytes
diff --git a/src/calibre/utils/config_base.py b/src/calibre/utils/config_base.py
index 0c8b1759a3..bc06642655 100644
--- a/src/calibre/utils/config_base.py
+++ b/src/calibre/utils/config_base.py
@@ -13,10 +13,7 @@ from contextlib import suppress
 from copy import deepcopy
 from functools import partial
 
-from calibre.constants import (
-    CONFIG_DIR_MODE, config_dir, filesystem_encoding, get_umask, iswindows,
-    preferred_encoding,
-)
+from calibre.constants import CONFIG_DIR_MODE, config_dir, filesystem_encoding, get_umask, iswindows, preferred_encoding
 from calibre.utils.localization import _
 from calibre.utils.resources import get_path as P
 from polyglot.builtins import iteritems
diff --git a/src/calibre/utils/copy_files_test.py b/src/calibre/utils/copy_files_test.py
index 9d884de31e..6e26eb71cb 100644
--- a/src/calibre/utils/copy_files_test.py
+++ b/src/calibre/utils/copy_files_test.py
@@ -13,6 +13,7 @@ from calibre.constants import iswindows
 
 from .copy_files import copy_tree, rename_files
 from .filenames import nlinks_file
+
 if iswindows:
     from calibre_extensions import winutil
 
diff --git a/src/calibre/utils/date.py b/src/calibre/utils/date.py
index 5d559350c0..045350002b 100644
--- a/src/calibre/utils/date.py
+++ b/src/calibre/utils/date.py
@@ -6,7 +6,8 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import re
-from datetime import MAXYEAR, MINYEAR, datetime, time as dtime, timedelta
+from datetime import MAXYEAR, MINYEAR, datetime, timedelta
+from datetime import time as dtime
 from functools import partial
 
 from calibre import strftime
@@ -156,7 +157,7 @@ def safeyear(x):
 
 
 def qt_to_dt(qdate_or_qdatetime, as_utc=True):
-    from qt.core import Qt, QDateTime
+    from qt.core import QDateTime, Qt
     o = qdate_or_qdatetime
     if o is None or is_date_undefined(qdate_or_qdatetime):
         return UNDEFINED_DATE
diff --git a/src/calibre/utils/filenames.py b/src/calibre/utils/filenames.py
index b76af7913c..f047ac1dd3 100644
--- a/src/calibre/utils/filenames.py
+++ b/src/calibre/utils/filenames.py
@@ -11,9 +11,7 @@ from contextlib import closing, suppress
 from math import ceil
 
 from calibre import force_unicode, isbytestring, prints, sanitize_file_name
-from calibre.constants import (
-    filesystem_encoding, ismacos, iswindows, preferred_encoding,
-)
+from calibre.constants import filesystem_encoding, ismacos, iswindows, preferred_encoding
 from calibre.utils.localization import _, get_udc
 from polyglot.builtins import iteritems, itervalues
 
diff --git a/src/calibre/utils/fonts/metadata.py b/src/calibre/utils/fonts/metadata.py
index 8a9ce83d1c..8d072ed674 100644
--- a/src/calibre/utils/fonts/metadata.py
+++ b/src/calibre/utils/fonts/metadata.py
@@ -5,10 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from io import BytesIO
 from collections import namedtuple
+from io import BytesIO
 
-from calibre.utils.fonts.utils import get_font_names_from_ttlib_names_table, get_font_characteristics
+from calibre.utils.fonts.utils import get_font_characteristics, get_font_names_from_ttlib_names_table
 
 
 class UnsupportedFont(ValueError):
@@ -24,7 +24,7 @@ FontNames = namedtuple('FontNames',
 class FontMetadata:
 
     def __init__(self, bytes_or_stream):
-        from fontTools.subset import load_font, Subsetter
+        from fontTools.subset import Subsetter, load_font
         if not hasattr(bytes_or_stream, 'read'):
             bytes_or_stream = BytesIO(bytes_or_stream)
         f = bytes_or_stream
diff --git a/src/calibre/utils/fonts/scanner.py b/src/calibre/utils/fonts/scanner.py
index 626e01299c..bfdc27e40d 100644
--- a/src/calibre/utils/fonts/scanner.py
+++ b/src/calibre/utils/fonts/scanner.py
@@ -10,11 +10,10 @@ from collections import defaultdict
 from threading import Thread
 
 from calibre import as_unicode, prints, walk
-from calibre.constants import (
-    DEBUG, config_dir, filesystem_encoding, ismacos, iswindows, isworker,
-)
+from calibre.constants import DEBUG, config_dir, filesystem_encoding, ismacos, iswindows, isworker
 from calibre.utils.fonts.metadata import FontMetadata, UnsupportedFont
-from calibre.utils.icu import lower as icu_lower, sort_key
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
 from calibre.utils.resources import get_path as P
 from polyglot.builtins import itervalues
 
@@ -269,9 +268,7 @@ class FontScanner(Thread):
 
         :return: (family name, faces) or None, None
         '''
-        from calibre.utils.fonts.utils import (
-            get_printable_characters, panose_to_css_generic_family, supports_text,
-        )
+        from calibre.utils.fonts.utils import get_printable_characters, panose_to_css_generic_family, supports_text
         if not isinstance(text, str):
             raise TypeError('%r is not unicode'%text)
         text = get_printable_characters(text)
diff --git a/src/calibre/utils/fonts/sfnt/cff/table.py b/src/calibre/utils/fonts/sfnt/cff/table.py
index 12b88bf33f..7a63813e6e 100644
--- a/src/calibre/utils/fonts/sfnt/cff/table.py
+++ b/src/calibre/utils/fonts/sfnt/cff/table.py
@@ -5,14 +5,13 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from struct import unpack_from, unpack, calcsize
 from functools import partial
+from struct import calcsize, unpack, unpack_from
 
 from calibre.utils.fonts.sfnt import UnknownTable
-from calibre.utils.fonts.sfnt.errors import UnsupportedFont, NoGlyphs
-from calibre.utils.fonts.sfnt.cff.dict_data import TopDict, PrivateDict
-from calibre.utils.fonts.sfnt.cff.constants import (cff_standard_strings,
-        STANDARD_CHARSETS)
+from calibre.utils.fonts.sfnt.cff.constants import STANDARD_CHARSETS, cff_standard_strings
+from calibre.utils.fonts.sfnt.cff.dict_data import PrivateDict, TopDict
+from calibre.utils.fonts.sfnt.errors import NoGlyphs, UnsupportedFont
 from polyglot.builtins import iteritems, itervalues
 
 # Useful links
diff --git a/src/calibre/utils/fonts/sfnt/cff/writer.py b/src/calibre/utils/fonts/sfnt/cff/writer.py
index 6d721c729b..1060c559a1 100644
--- a/src/calibre/utils/fonts/sfnt/cff/writer.py
+++ b/src/calibre/utils/fonts/sfnt/cff/writer.py
@@ -5,8 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from struct import pack
 from collections import OrderedDict
+from struct import pack
 
 from calibre.utils.fonts.sfnt.cff.constants import cff_standard_strings
 
diff --git a/src/calibre/utils/fonts/sfnt/cmap.py b/src/calibre/utils/fonts/sfnt/cmap.py
index fedb35340b..7e9f5bb6a1 100644
--- a/src/calibre/utils/fonts/sfnt/cmap.py
+++ b/src/calibre/utils/fonts/sfnt/cmap.py
@@ -8,12 +8,12 @@ __docformat__ = 'restructuredtext en'
 # Note that the code for creating a BMP table (cmap format 4) is taken with
 # thanks from the fonttools project (BSD licensed).
 
-from struct import unpack_from, calcsize, pack
 from collections import OrderedDict
+from struct import calcsize, pack, unpack_from
 
-from calibre.utils.fonts.utils import read_bmp_prefix
 from calibre.utils.fonts.sfnt import UnknownTable, max_power_of_two
 from calibre.utils.fonts.sfnt.errors import UnsupportedFont
+from calibre.utils.fonts.utils import read_bmp_prefix
 
 
 def split_range(start_code, end_code, cmap):  # {{{
diff --git a/src/calibre/utils/fonts/sfnt/common.py b/src/calibre/utils/fonts/sfnt/common.py
index 14cca787c4..8fd02a03a2 100644
--- a/src/calibre/utils/fonts/sfnt/common.py
+++ b/src/calibre/utils/fonts/sfnt/common.py
@@ -5,8 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from struct import unpack_from, calcsize
 from collections import OrderedDict, namedtuple
+from struct import calcsize, unpack_from
 
 from calibre.utils.fonts.sfnt.errors import UnsupportedFont
 from polyglot.builtins import iteritems
diff --git a/src/calibre/utils/fonts/sfnt/container.py b/src/calibre/utils/fonts/sfnt/container.py
index 93cf47e08a..6c29f3ba5f 100644
--- a/src/calibre/utils/fonts/sfnt/container.py
+++ b/src/calibre/utils/fonts/sfnt/container.py
@@ -12,9 +12,7 @@ from calibre.utils.fonts.sfnt.cmap import CmapTable
 from calibre.utils.fonts.sfnt.errors import UnsupportedFont
 from calibre.utils.fonts.sfnt.glyf import GlyfTable
 from calibre.utils.fonts.sfnt.gsub import GSUBTable
-from calibre.utils.fonts.sfnt.head import (
-    HeadTable, HorizontalHeader, OS2Table, PostTable, VerticalHeader,
-)
+from calibre.utils.fonts.sfnt.head import HeadTable, HorizontalHeader, OS2Table, PostTable, VerticalHeader
 from calibre.utils.fonts.sfnt.kern import KernTable
 from calibre.utils.fonts.sfnt.loca import LocaTable
 from calibre.utils.fonts.sfnt.maxp import MaxpTable
diff --git a/src/calibre/utils/fonts/sfnt/glyf.py b/src/calibre/utils/fonts/sfnt/glyf.py
index 139f727a18..abb648eafe 100644
--- a/src/calibre/utils/fonts/sfnt/glyf.py
+++ b/src/calibre/utils/fonts/sfnt/glyf.py
@@ -5,8 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from struct import unpack_from
 from collections import OrderedDict
+from struct import unpack_from
 
 from calibre.utils.fonts.sfnt import UnknownTable
 from polyglot.builtins import iteritems
diff --git a/src/calibre/utils/fonts/sfnt/gsub.py b/src/calibre/utils/fonts/sfnt/gsub.py
index 0597ec082b..e1ffc8d426 100644
--- a/src/calibre/utils/fonts/sfnt/gsub.py
+++ b/src/calibre/utils/fonts/sfnt/gsub.py
@@ -5,14 +5,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from struct import unpack_from
 from functools import partial
+from struct import unpack_from
 
-from calibre.utils.fonts.sfnt import UnknownTable, FixedProperty
+from calibre.utils.fonts.sfnt import FixedProperty, UnknownTable
+from calibre.utils.fonts.sfnt.common import ExtensionSubstitution, FeatureListTable, LookupTable, ScriptListTable, SimpleListTable, UnknownLookupSubTable
 from calibre.utils.fonts.sfnt.errors import UnsupportedFont
-from calibre.utils.fonts.sfnt.common import (ScriptListTable, FeatureListTable,
-        SimpleListTable, LookupTable, ExtensionSubstitution,
-        UnknownLookupSubTable)
 from polyglot.builtins import iteritems, itervalues
 
 
diff --git a/src/calibre/utils/fonts/sfnt/head.py b/src/calibre/utils/fonts/sfnt/head.py
index 6c6b79c33d..a97bf47371 100644
--- a/src/calibre/utils/fonts/sfnt/head.py
+++ b/src/calibre/utils/fonts/sfnt/head.py
@@ -6,9 +6,9 @@ __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import array
-from struct import unpack_from, pack, calcsize
+from struct import calcsize, pack, unpack_from
 
-from calibre.utils.fonts.sfnt import UnknownTable, DateTimeProperty, FixedProperty
+from calibre.utils.fonts.sfnt import DateTimeProperty, FixedProperty, UnknownTable
 from calibre.utils.fonts.sfnt.errors import UnsupportedFont
 from calibre.utils.fonts.sfnt.loca import read_array
 
diff --git a/src/calibre/utils/fonts/sfnt/kern.py b/src/calibre/utils/fonts/sfnt/kern.py
index f8d1aacf39..11e782fb98 100644
--- a/src/calibre/utils/fonts/sfnt/kern.py
+++ b/src/calibre/utils/fonts/sfnt/kern.py
@@ -5,10 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from struct import unpack_from, calcsize, pack, error as struct_error
+from struct import calcsize, pack, unpack_from
+from struct import error as struct_error
 
-from calibre.utils.fonts.sfnt import (UnknownTable, FixedProperty,
-        max_power_of_two)
+from calibre.utils.fonts.sfnt import FixedProperty, UnknownTable, max_power_of_two
 from calibre.utils.fonts.sfnt.errors import UnsupportedFont
 
 
diff --git a/src/calibre/utils/fonts/sfnt/loca.py b/src/calibre/utils/fonts/sfnt/loca.py
index 1cd1ef7424..1f79d8b68a 100644
--- a/src/calibre/utils/fonts/sfnt/loca.py
+++ b/src/calibre/utils/fonts/sfnt/loca.py
@@ -5,9 +5,10 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import array, sys
-from operator import itemgetter
+import array
+import sys
 from itertools import repeat
+from operator import itemgetter
 
 from calibre.utils.fonts.sfnt import UnknownTable
 from polyglot.builtins import iteritems
diff --git a/src/calibre/utils/fonts/sfnt/maxp.py b/src/calibre/utils/fonts/sfnt/maxp.py
index 0f0ef23b37..6570e7b2b2 100644
--- a/src/calibre/utils/fonts/sfnt/maxp.py
+++ b/src/calibre/utils/fonts/sfnt/maxp.py
@@ -5,9 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from struct import unpack_from, pack
+from struct import pack, unpack_from
 
-from calibre.utils.fonts.sfnt import UnknownTable, FixedProperty
+from calibre.utils.fonts.sfnt import FixedProperty, UnknownTable
 from calibre.utils.fonts.sfnt.errors import UnsupportedFont
 
 
diff --git a/src/calibre/utils/fonts/sfnt/metrics.py b/src/calibre/utils/fonts/sfnt/metrics.py
index 7cebc3518a..5207c57480 100644
--- a/src/calibre/utils/fonts/sfnt/metrics.py
+++ b/src/calibre/utils/fonts/sfnt/metrics.py
@@ -5,8 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-from calibre.utils.fonts.utils import get_all_font_names
 from calibre.utils.fonts.sfnt.container import UnsupportedFont
+from calibre.utils.fonts.utils import get_all_font_names
 
 
 class FontMetrics:
@@ -113,6 +113,7 @@ class FontMetrics:
 
 if __name__ == '__main__':
     import sys
+
     from calibre.utils.fonts.sfnt.container import Sfnt
     with open(sys.argv[-1], 'rb') as f:
         raw = f.read()
diff --git a/src/calibre/utils/fonts/subset.py b/src/calibre/utils/fonts/subset.py
index 3a9c5b5eb2..40f5076e45 100644
--- a/src/calibre/utils/fonts/subset.py
+++ b/src/calibre/utils/fonts/subset.py
@@ -7,7 +7,6 @@ from logging.handlers import QueueHandler
 from queue import Empty, SimpleQueue
 
 
-
 def subset(input_file_object_or_path, output_file_object_or_path, container_type, chars_or_text=''):
     from fontTools.subset import Subsetter, load_font, log, save_font
     log_messages = SimpleQueue()
diff --git a/src/calibre/utils/fonts/win_fonts.py b/src/calibre/utils/fonts/win_fonts.py
index 3411a73ce2..ca659e492c 100644
--- a/src/calibre/utils/fonts/win_fonts.py
+++ b/src/calibre/utils/fonts/win_fonts.py
@@ -5,14 +5,15 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, sys, atexit
+import atexit
+import os
+import sys
 from itertools import product
 
-from calibre import prints, isbytestring
-from calibre.utils.resources import get_path as P
+from calibre import isbytestring, prints
 from calibre.constants import filesystem_encoding
-from calibre.utils.fonts.utils import (is_truetype_font, get_font_names,
-        get_font_characteristics)
+from calibre.utils.fonts.utils import get_font_characteristics, get_font_names, is_truetype_font
+from calibre.utils.resources import get_path as P
 from polyglot.builtins import iteritems
 
 
diff --git a/src/calibre/utils/formatter.py b/src/calibre/utils/formatter.py
index ab7934cc6a..8f09febd84 100644
--- a/src/calibre/utils/formatter.py
+++ b/src/calibre/utils/formatter.py
@@ -20,9 +20,7 @@ from calibre import prints
 from calibre.constants import DEBUG
 from calibre.ebooks.metadata.book.base import field_metadata
 from calibre.utils.config import tweaks
-from calibre.utils.formatter_functions import (
-    StoredObjectType, formatter_functions, function_object_type, get_database,
-)
+from calibre.utils.formatter_functions import StoredObjectType, formatter_functions, function_object_type, get_database
 from calibre.utils.icu import strcmp
 from calibre.utils.localization import _
 from polyglot.builtins import error_message
diff --git a/src/calibre/utils/formatter_functions.py b/src/calibre/utils/formatter_functions.py
index c4adfa9750..6666b01283 100644
--- a/src/calibre/utils/formatter_functions.py
+++ b/src/calibre/utils/formatter_functions.py
@@ -20,17 +20,19 @@ from contextlib import suppress
 from datetime import datetime, timedelta
 from enum import Enum, auto
 from functools import partial
-from lxml import html
 from math import ceil, floor, modf, trunc
 
+from lxml import html
+
 from calibre import human_readable, prepare_string_for_xml, prints
 from calibre.constants import DEBUG
 from calibre.db.constants import DATA_DIR_NAME, DATA_FILE_PATTERN
-from calibre.db.notes.exim import parse_html, expand_note_resources
+from calibre.db.notes.exim import expand_note_resources, parse_html
 from calibre.ebooks.metadata import title_sort
 from calibre.utils.config import tweaks
 from calibre.utils.date import UNDEFINED_DATE, format_date, now, parse_date
-from calibre.utils.icu import capitalize, lower as icu_lower, sort_key, strcmp
+from calibre.utils.icu import capitalize, sort_key, strcmp
+from calibre.utils.icu import lower as icu_lower
 from calibre.utils.localization import _, calibre_langcode_to_name, canonicalize_lang
 from calibre.utils.titlecase import titlecase
 from polyglot.builtins import iteritems, itervalues
diff --git a/src/calibre/utils/html2text.py b/src/calibre/utils/html2text.py
index 4dc0643864..65e1581a4e 100644
--- a/src/calibre/utils/html2text.py
+++ b/src/calibre/utils/html2text.py
@@ -6,8 +6,9 @@ from calibre.utils.localization import _
 
 
 def html2text(html, single_line_break=True, default_image_alt=''):
-    from html2text import HTML2Text
     import re
+
+    from html2text import HTML2Text
     if isinstance(html, bytes):
         from calibre.ebooks.chardet import xml_to_unicode
         html = xml_to_unicode(html, strip_encoding_pats=True, resolve_entities=True)[0]
diff --git a/src/calibre/utils/https.py b/src/calibre/utils/https.py
index 84395de07f..05878aed51 100644
--- a/src/calibre/utils/https.py
+++ b/src/calibre/utils/https.py
@@ -4,13 +4,16 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import ssl, socket, re
+import re
+import socket
+import ssl
 from contextlib import closing
 
 from calibre import get_proxies
 from calibre.utils.resources import get_path as P
 from polyglot import http_client
 from polyglot.urllib import urlsplit
+
 has_ssl_verify = hasattr(ssl, 'create_default_context') and hasattr(ssl, '_create_unverified_context')
 
 
diff --git a/src/calibre/utils/hyphenation/dictionaries.py b/src/calibre/utils/hyphenation/dictionaries.py
index 1d562f27ee..000f0b7825 100644
--- a/src/calibre/utils/hyphenation/dictionaries.py
+++ b/src/calibre/utils/hyphenation/dictionaries.py
@@ -10,9 +10,9 @@ from io import BytesIO
 
 from calibre.constants import cache_dir
 from calibre.ptempfile import TemporaryDirectory
-from calibre.utils.resources import get_path as P
 from calibre.utils.localization import lang_as_iso639_1
 from calibre.utils.lock import ExclusiveFile
+from calibre.utils.resources import get_path as P
 from polyglot.builtins import iteritems
 from polyglot.functools import lru_cache
 
diff --git a/src/calibre/utils/hyphenation/hyphenate.py b/src/calibre/utils/hyphenation/hyphenate.py
index dd38e63897..d446b849f0 100644
--- a/src/calibre/utils/hyphenation/hyphenate.py
+++ b/src/calibre/utils/hyphenation/hyphenate.py
@@ -6,9 +6,7 @@ import os
 
 import regex
 
-from calibre.utils.hyphenation.dictionaries import (
-    dictionary_name_for_locale, path_to_dictionary
-)
+from calibre.utils.hyphenation.dictionaries import dictionary_name_for_locale, path_to_dictionary
 from polyglot.functools import lru_cache
 
 REGEX_FLAGS = regex.VERSION1 | regex.WORD | regex.FULLCASE | regex.UNICODE
diff --git a/src/calibre/utils/hyphenation/test_hyphenation.py b/src/calibre/utils/hyphenation/test_hyphenation.py
index aa915d8099..57ce503c3b 100644
--- a/src/calibre/utils/hyphenation/test_hyphenation.py
+++ b/src/calibre/utils/hyphenation/test_hyphenation.py
@@ -10,14 +10,8 @@ from lxml import etree
 
 from calibre.ebooks.oeb.polish.parsing import parse_html5
 from calibre.ptempfile import PersistentTemporaryDirectory
-from calibre.utils.hyphenation.dictionaries import (
-    dictionary_name_for_locale, get_cache_path, is_cache_up_to_date,
-    path_to_dictionary
-)
-from calibre.utils.hyphenation.hyphenate import (
-    add_soft_hyphens, add_soft_hyphens_to_html, add_soft_hyphens_to_words,
-    dictionary_for_locale
-)
+from calibre.utils.hyphenation.dictionaries import dictionary_name_for_locale, get_cache_path, is_cache_up_to_date, path_to_dictionary
+from calibre.utils.hyphenation.hyphenate import add_soft_hyphens, add_soft_hyphens_to_html, add_soft_hyphens_to_words, dictionary_for_locale
 
 
 class TestHyphenation(unittest.TestCase):
diff --git a/src/calibre/utils/icu.py b/src/calibre/utils/icu.py
index 19ad044954..24c3450b97 100644
--- a/src/calibre/utils/icu.py
+++ b/src/calibre/utils/icu.py
@@ -318,8 +318,9 @@ def remove_accents_icu(txt: str) -> str:
 def remove_accents_regex(txt: str) -> str:
     pat = getattr(remove_accents_regex, 'pat', None)
     if pat is None:
-        import regex
         import unicodedata
+
+        import regex
         pat = regex.compile(r'\p{Mn}', flags=regex.UNICODE)
         setattr(remove_accents_regex, 'pat', pat)
         setattr(remove_accents_regex, 'normalize', unicodedata.normalize)
diff --git a/src/calibre/utils/icu_test.py b/src/calibre/utils/icu_test.py
index f7d6377c40..e4e9a17887 100644
--- a/src/calibre/utils/icu_test.py
+++ b/src/calibre/utils/icu_test.py
@@ -4,11 +4,12 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import unittest, sys
+import sys
+import unittest
 from contextlib import contextmanager
 
 import calibre.utils.icu as icu
-from polyglot.builtins import iteritems, cmp
+from polyglot.builtins import cmp, iteritems
 
 
 @contextmanager
@@ -201,7 +202,8 @@ class TestICU(unittest.TestCase):
 
     def test_break_iterator(self):
         ' Test the break iterator '
-        from calibre.spell.break_iterator import split_into_words as split, index_of, split_into_words_and_positions, count_words
+        from calibre.spell.break_iterator import count_words, index_of, split_into_words_and_positions
+        from calibre.spell.break_iterator import split_into_words as split
         for q in ('one two three', ' one two three', 'one\ntwo  three ', ):
             self.ae(split(str(q)), ['one', 'two', 'three'], 'Failed to split: %r' % q)
         self.ae(split('I I\'m'), ['I', "I'm"])
diff --git a/src/calibre/utils/img.py b/src/calibre/utils/img.py
index a420700f94..d2be1251ad 100644
--- a/src/calibre/utils/img.py
+++ b/src/calibre/utils/img.py
@@ -10,12 +10,10 @@ import sys
 import tempfile
 from contextlib import suppress
 from io import BytesIO
-from qt.core import (
-    QBuffer, QByteArray, QColor, QImage, QImageReader, QImageWriter, QIODevice, QPixmap,
-    Qt, QTransform, qRgba
-)
 from threading import Thread
 
+from qt.core import QBuffer, QByteArray, QColor, QImage, QImageReader, QImageWriter, QIODevice, QPixmap, Qt, QTransform, qRgba
+
 from calibre import fit_image, force_unicode
 from calibre.constants import iswindows
 from calibre.ptempfile import TemporaryDirectory
@@ -110,9 +108,7 @@ def gif_data_to_png_data(data, discard_animation=False):
 
 def set_image_allocation_limit(size_in_mb=1024):
     with suppress(ImportError):  # for people running form source
-        from calibre_extensions.progress_indicator import (
-            set_image_allocation_limit as impl,
-        )
+        from calibre_extensions.progress_indicator import set_image_allocation_limit as impl
         impl(size_in_mb)
 
 
diff --git a/src/calibre/utils/imghdr.py b/src/calibre/utils/imghdr.py
index e23c4f8d17..186b71c081 100644
--- a/src/calibre/utils/imghdr.py
+++ b/src/calibre/utils/imghdr.py
@@ -2,8 +2,9 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from struct import unpack, error
 import os
+from struct import error, unpack
+
 from calibre.utils.speedups import ReadOnlyFileBuffer
 from polyglot.builtins import string_or_bytes
 
diff --git a/src/calibre/utils/inotify.py b/src/calibre/utils/inotify.py
index 65c686c534..6941215999 100644
--- a/src/calibre/utils/inotify.py
+++ b/src/calibre/utils/inotify.py
@@ -4,7 +4,10 @@
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, os, errno, select
+import errno
+import os
+import select
+import sys
 
 
 class INotifyError(Exception):
@@ -115,7 +118,8 @@ class INotify:
     NONBLOCK = 0x800
 
     def __init__(self, cloexec=True, nonblock=True):
-        import ctypes, struct
+        import ctypes
+        import struct
         self._init1, self._add_watch, self._rm_watch, self._read = load_inotify()
         flags = 0
         if cloexec:
diff --git a/src/calibre/utils/ip_routing.py b/src/calibre/utils/ip_routing.py
index 35ec8b0891..3b847bf6f7 100644
--- a/src/calibre/utils/ip_routing.py
+++ b/src/calibre/utils/ip_routing.py
@@ -2,8 +2,10 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import subprocess, re
-from calibre.constants import iswindows, ismacos
+import re
+import subprocess
+
+from calibre.constants import ismacos, iswindows
 
 
 def get_address_of_default_gateway(family='AF_INET'):
diff --git a/src/calibre/utils/ipc/__init__.py b/src/calibre/utils/ipc/__init__.py
index 05898a1388..b3a007198f 100644
--- a/src/calibre/utils/ipc/__init__.py
+++ b/src/calibre/utils/ipc/__init__.py
@@ -9,9 +9,7 @@ import errno
 import os
 
 from calibre import force_unicode
-from calibre.constants import (
-    filesystem_encoding, get_windows_username, islinux, iswindows
-)
+from calibre.constants import filesystem_encoding, get_windows_username, islinux, iswindows
 from calibre.utils.filenames import ascii_filename
 from polyglot.functools import lru_cache
 
diff --git a/src/calibre/utils/ipc/launch.py b/src/calibre/utils/ipc/launch.py
index 533bc7eba5..12475b8c01 100644
--- a/src/calibre/utils/ipc/launch.py
+++ b/src/calibre/utils/ipc/launch.py
@@ -4,14 +4,17 @@ __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import subprocess, os, sys, time
+import os
+import subprocess
+import sys
+import time
 
-from calibre.constants import iswindows, ismacos, isfrozen
-from calibre.utils.config import prefs
+from calibre.constants import isfrozen, ismacos, iswindows
 from calibre.ptempfile import PersistentTemporaryFile, base_dir
+from calibre.utils.config import prefs
 from calibre.utils.serialize import msgpack_dumps
-from polyglot.builtins import string_or_bytes, environ_item, native_string_type
 from polyglot.binary import as_hex_unicode
+from polyglot.builtins import environ_item, native_string_type, string_or_bytes
 
 if iswindows:
     try:
diff --git a/src/calibre/utils/ipc/pool.py b/src/calibre/utils/ipc/pool.py
index a94b3ac106..4bc15d1668 100644
--- a/src/calibre/utils/ipc/pool.py
+++ b/src/calibre/utils/ipc/pool.py
@@ -4,13 +4,14 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, sys
-from threading import Thread
+import os
+import sys
 from collections import namedtuple
 from multiprocessing.connection import Pipe
+from threading import Thread
 
-from calibre import detect_ncpus, as_unicode, prints
-from calibre.constants import iswindows, DEBUG
+from calibre import as_unicode, detect_ncpus, prints
+from calibre.constants import DEBUG, iswindows
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.utils import join_with_timeout
 from calibre.utils.ipc import eintr_retry_call
diff --git a/src/calibre/utils/ipc/server.py b/src/calibre/utils/ipc/server.py
index 29766cfdae..4f66b73f71 100644
--- a/src/calibre/utils/ipc/server.py
+++ b/src/calibre/utils/ipc/server.py
@@ -16,7 +16,8 @@ from math import ceil
 from multiprocessing import Pipe
 from threading import Thread
 
-from calibre import detect_ncpus as cpu_count, force_unicode
+from calibre import detect_ncpus as cpu_count
+from calibre import force_unicode
 from calibre.constants import DEBUG
 from calibre.ptempfile import base_dir
 from calibre.utils.ipc import eintr_retry_call
@@ -27,7 +28,6 @@ from polyglot.binary import as_hex_unicode
 from polyglot.builtins import environ_item, string_or_bytes
 from polyglot.queue import Empty, Queue
 
-
 server_counter = count()
 _name_counter = count()
 
diff --git a/src/calibre/utils/iphlpapi.py b/src/calibre/utils/iphlpapi.py
index 55473c8fbe..7295aca1aa 100644
--- a/src/calibre/utils/iphlpapi.py
+++ b/src/calibre/utils/iphlpapi.py
@@ -3,10 +3,9 @@
 
 
 import ctypes
-from ctypes import windll
-from ctypes import wintypes
 from collections import namedtuple
 from contextlib import contextmanager
+from ctypes import windll, wintypes
 
 # Wraps (part of) the IPHelper API, useful to enumerate the network routes and
 # adapters on the local machine
diff --git a/src/calibre/utils/ipython.py b/src/calibre/utils/ipython.py
index 5b53747fc9..a2f19bf29f 100644
--- a/src/calibre/utils/ipython.py
+++ b/src/calibre/utils/ipython.py
@@ -5,8 +5,11 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, re, sys
-from calibre.constants import iswindows, cache_dir, get_version
+import os
+import re
+import sys
+
+from calibre.constants import cache_dir, get_version, iswindows
 from polyglot.builtins import exec_path
 
 ipydir = os.path.join(cache_dir(), 'ipython')
@@ -115,7 +118,9 @@ history_length(2000) #value of -1 means no limit
         with open(conf, 'wb') as f:
             f.write(config.encode('utf-8'))
         pyreadline.rlmain.config_path = conf
-        import readline, atexit
+        import atexit
+        import readline
+
         import pyreadline.unicode_helper  # noqa
         # Normally the codepage for pyreadline is set to be sys.stdout.encoding
         # if you need to change this uncomment the following line
@@ -189,8 +194,8 @@ def ipython(user_ns=None):
     have_ipython = True
     try:
         from IPython.terminal.embed import InteractiveShellEmbed
-        from traitlets.config.loader import Config
         from IPython.terminal.prompts import Prompts, Token
+        from traitlets.config.loader import Config
     except ImportError:
         have_ipython = False
     if not have_ipython:
diff --git a/src/calibre/utils/linux_trash.py b/src/calibre/utils/linux_trash.py
index f2309ca6d9..ebc4eea4bd 100644
--- a/src/calibre/utils/linux_trash.py
+++ b/src/calibre/utils/linux_trash.py
@@ -17,10 +17,11 @@
 # For external volumes this implementation will raise an exception if it can't
 # find or create the user's trash directory.
 
-import os, stat
+import os
 import os.path as op
-from datetime import datetime
 import shutil
+import stat
+from datetime import datetime
 
 from polyglot.urllib import quote
 
diff --git a/src/calibre/utils/localunzip.py b/src/calibre/utils/localunzip.py
index 957865f9d3..31923806c8 100644
--- a/src/calibre/utils/localunzip.py
+++ b/src/calibre/utils/localunzip.py
@@ -12,11 +12,14 @@ These are apparently produced in large numbers by the fruitcakes over at B&N.
 Tries to only use the local headers to extract data from the damaged zip file.
 '''
 
-import os, sys, zlib, shutil
-from struct import calcsize, unpack, pack
-from collections import namedtuple, OrderedDict
-from calibre.ptempfile import SpooledTemporaryFile
+import os
+import shutil
+import sys
+import zlib
+from collections import OrderedDict, namedtuple
+from struct import calcsize, pack, unpack
 
+from calibre.ptempfile import SpooledTemporaryFile
 from polyglot.builtins import itervalues
 
 HEADER_SIG = 0x04034b50
diff --git a/src/calibre/utils/lock.py b/src/calibre/utils/lock.py
index ab301018b2..e96de47d83 100644
--- a/src/calibre/utils/lock.py
+++ b/src/calibre/utils/lock.py
@@ -9,14 +9,13 @@ import tempfile
 import time
 from functools import partial
 
-from calibre.constants import (
-    __appname__, filesystem_encoding, islinux, ismacos, iswindows
-)
-from calibre_extensions import speedup
+from calibre.constants import __appname__, filesystem_encoding, islinux, ismacos, iswindows
 from calibre.utils.monotonic import monotonic
+from calibre_extensions import speedup
 
 if iswindows:
     import msvcrt
+
     from calibre.constants import get_windows_username
     from calibre_extensions import winutil
     excl_file_mode = stat.S_IREAD | stat.S_IWRITE
@@ -141,6 +140,7 @@ elif islinux:
 
     def create_single_instance_mutex(name, per_user=True):
         import socket
+
         from calibre.utils.ipc import eintr_retry_call
         name = '{}-singleinstance-{}-{}'.format(
             __appname__, (os.geteuid() if per_user else ''), name
diff --git a/src/calibre/utils/logging.py b/src/calibre/utils/logging.py
index 2f16a158b5..059b1e2fdb 100644
--- a/src/calibre/utils/logging.py
+++ b/src/calibre/utils/logging.py
@@ -13,7 +13,6 @@ from threading import Lock
 from calibre.prints import prints
 from polyglot.builtins import as_unicode
 
-
 DEBUG = 0
 INFO  = 1
 WARN  = 2
diff --git a/src/calibre/utils/magick/draw.py b/src/calibre/utils/magick/draw.py
index 3794dfe9e0..ce3a7d3d8c 100644
--- a/src/calibre/utils/magick/draw.py
+++ b/src/calibre/utils/magick/draw.py
@@ -7,10 +7,12 @@ __docformat__ = 'restructuredtext en'
 
 import os
 
-from calibre.utils.magick import Image, create_canvas
-from calibre.utils.img import save_cover_data_to as _save_cover_data_to, image_to_data, add_borders_to_image as abti
-from calibre.utils.imghdr import identify as _identify
 from calibre import fit_image
+from calibre.utils.img import add_borders_to_image as abti
+from calibre.utils.img import image_to_data
+from calibre.utils.img import save_cover_data_to as _save_cover_data_to
+from calibre.utils.imghdr import identify as _identify
+from calibre.utils.magick import Image, create_canvas
 
 
 def _data_to_image(data):
diff --git a/src/calibre/utils/magick/legacy.py b/src/calibre/utils/magick/legacy.py
index 651a0bd56e..fc3c66c96b 100644
--- a/src/calibre/utils/magick/legacy.py
+++ b/src/calibre/utils/magick/legacy.py
@@ -6,11 +6,25 @@ import os
 from io import BytesIO
 
 from calibre.utils.img import (
-    image_and_format_from_data, clone_image, null_image, resize_image,
-    overlay_image, rotate_image, quantize_image, remove_borders_from_image,
-    add_borders_to_image, gaussian_blur_image, create_canvas, despeckle_image,
-    image_to_data, flip_image, image_has_transparent_pixels, set_image_opacity,
-    gaussian_sharpen_image, texture_image, grayscale_image
+    add_borders_to_image,
+    clone_image,
+    create_canvas,
+    despeckle_image,
+    flip_image,
+    gaussian_blur_image,
+    gaussian_sharpen_image,
+    grayscale_image,
+    image_and_format_from_data,
+    image_has_transparent_pixels,
+    image_to_data,
+    null_image,
+    overlay_image,
+    quantize_image,
+    remove_borders_from_image,
+    resize_image,
+    rotate_image,
+    set_image_opacity,
+    texture_image,
 )
 from calibre.utils.imghdr import identify
 
diff --git a/src/calibre/utils/matcher.py b/src/calibre/utils/matcher.py
index aac31436e0..c08fee8e58 100644
--- a/src/calibre/utils/matcher.py
+++ b/src/calibre/utils/matcher.py
@@ -14,12 +14,12 @@ from operator import itemgetter
 from threading import Lock, Thread
 from unicodedata import normalize
 
-from calibre import as_unicode, detect_ncpus as cpu_count
+from calibre import as_unicode
+from calibre import detect_ncpus as cpu_count
 from calibre.constants import filesystem_encoding
-from calibre.utils.icu import (
-    lower as icu_lower, primary_collator, primary_find, primary_sort_key,
-    upper as icu_upper,
-)
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import primary_collator, primary_find, primary_sort_key
+from calibre.utils.icu import upper as icu_upper
 from polyglot.builtins import iteritems, itervalues
 from polyglot.queue import Queue
 
diff --git a/src/calibre/utils/mdns.py b/src/calibre/utils/mdns.py
index 696706b9e8..db84d4cc64 100644
--- a/src/calibre/utils/mdns.py
+++ b/src/calibre/utils/mdns.py
@@ -2,12 +2,14 @@ __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import socket, time, atexit
+import atexit
+import socket
+import time
 from collections import defaultdict
 from threading import Thread
 
-from calibre.utils.filenames import ascii_text
 from calibre import force_unicode
+from calibre.utils.filenames import ascii_text
 
 _server = None
 
diff --git a/src/calibre/utils/mem.py b/src/calibre/utils/mem.py
index 9ed0ea1a30..ce286b04ca 100644
--- a/src/calibre/utils/mem.py
+++ b/src/calibre/utils/mem.py
@@ -13,7 +13,8 @@ You can pass a number to memory and it will be subtracted from the returned
 value.
 '''
 
-import gc, os
+import gc
+import os
 
 
 def get_memory():
diff --git a/src/calibre/utils/monotonic.py b/src/calibre/utils/monotonic.py
index d836867569..793af1266a 100644
--- a/src/calibre/utils/monotonic.py
+++ b/src/calibre/utils/monotonic.py
@@ -1,2 +1,3 @@
 from time import monotonic
+
 monotonic
diff --git a/src/calibre/utils/mreplace.py b/src/calibre/utils/mreplace.py
index 41ce0bcf36..65b9cdcd65 100644
--- a/src/calibre/utils/mreplace.py
+++ b/src/calibre/utils/mreplace.py
@@ -5,6 +5,7 @@ __copyright__ = '2010, sengian <sengian1 @ gmail.com>'
 __docformat__ = 'restructuredtext en'
 
 import re
+
 try:
     from collections import UserDict
 except ImportError:
diff --git a/src/calibre/utils/open_with/linux.py b/src/calibre/utils/open_with/linux.py
index 4cdaa80bee..3edb4fbc64 100644
--- a/src/calibre/utils/open_with/linux.py
+++ b/src/calibre/utils/open_with/linux.py
@@ -4,11 +4,13 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import re, shlex, os
+import os
+import re
+import shlex
 from collections import defaultdict
 
-from calibre import walk, guess_type, prints, force_unicode
-from calibre.constants import filesystem_encoding, cache_dir
+from calibre import force_unicode, guess_type, prints, walk
+from calibre.constants import cache_dir, filesystem_encoding
 from calibre.utils.icu import numeric_sort_key as sort_key
 from calibre.utils.localization import canonicalize_lang, get_lang
 from calibre.utils.serialize import msgpack_dumps, msgpack_loads
diff --git a/src/calibre/utils/open_with/osx.py b/src/calibre/utils/open_with/osx.py
index 9cb4c079cd..5adae681d8 100644
--- a/src/calibre/utils/open_with/osx.py
+++ b/src/calibre/utils/open_with/osx.py
@@ -4,7 +4,10 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, re, mimetypes, subprocess
+import mimetypes
+import os
+import re
+import subprocess
 from collections import defaultdict
 from plistlib import loads
 
@@ -18,9 +21,10 @@ application_locations = ('/Applications', '~/Applications', '~/Desktop')
 
 
 def generate_public_uti_map():
-    from lxml import etree
-    from polyglot.urllib import urlopen
     from html5_parser import parse
+    from lxml import etree
+
+    from polyglot.urllib import urlopen
     raw = urlopen(
         'https://developer.apple.com/library/ios/documentation/Miscellaneous/Reference/UTIRef/Articles/System-DeclaredUniformTypeIdentifiers.html').read()
     root = parse(raw)
diff --git a/src/calibre/utils/open_with/windows.py b/src/calibre/utils/open_with/windows.py
index 79d0f40669..2c58ee1e3c 100644
--- a/src/calibre/utils/open_with/windows.py
+++ b/src/calibre/utils/open_with/windows.py
@@ -7,6 +7,7 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 import os
 import re
 import sys
+
 from qt.core import QBuffer, QByteArray, QIODevice, QPixmap, Qt
 
 from calibre.gui2 import must_use_qt
diff --git a/src/calibre/utils/opensearch/description.py b/src/calibre/utils/opensearch/description.py
index 059694d0f2..f1bada0926 100644
--- a/src/calibre/utils/opensearch/description.py
+++ b/src/calibre/utils/opensearch/description.py
@@ -8,8 +8,8 @@ __docformat__ = 'restructuredtext en'
 from contextlib import closing
 
 from calibre import browser
-from calibre.utils.xml_parse import safe_xml_fromstring
 from calibre.utils.opensearch.url import URL
+from calibre.utils.xml_parse import safe_xml_fromstring
 
 
 class Description:
diff --git a/src/calibre/utils/podofo/__init__.py b/src/calibre/utils/podofo/__init__.py
index cd29451bc9..68c84180fa 100644
--- a/src/calibre/utils/podofo/__init__.py
+++ b/src/calibre/utils/podofo/__init__.py
@@ -213,6 +213,7 @@ def test_roundtrip(src, dest):
 
 def test_podofo():
     import tempfile
+
     from calibre.ebooks.metadata.book.base import Metadata
     from calibre.ebooks.metadata.xmp import metadata_to_xmp_packet
     # {{{
diff --git a/src/calibre/utils/random_ua.py b/src/calibre/utils/random_ua.py
index 35f46e639f..8c9db5253a 100644
--- a/src/calibre/utils/random_ua.py
+++ b/src/calibre/utils/random_ua.py
@@ -4,6 +4,7 @@
 
 import json
 import random
+
 from calibre.utils.resources import get_path as P
 
 
diff --git a/src/calibre/utils/rapydscript.py b/src/calibre/utils/rapydscript.py
index 1933808ec2..c46f582410 100644
--- a/src/calibre/utils/rapydscript.py
+++ b/src/calibre/utils/rapydscript.py
@@ -11,9 +11,15 @@ import sys
 
 from calibre import force_unicode
 from calibre.constants import (
-    FAKE_HOST, FAKE_PROTOCOL, SPECIAL_TITLE_FOR_WEBENGINE_COMMS, __appname__,
-    __version__, builtin_colors_dark, builtin_colors_light, builtin_decorations,
-    dark_link_color
+    FAKE_HOST,
+    FAKE_PROTOCOL,
+    SPECIAL_TITLE_FOR_WEBENGINE_COMMS,
+    __appname__,
+    __version__,
+    builtin_colors_dark,
+    builtin_colors_light,
+    builtin_decorations,
+    dark_link_color,
 )
 from calibre.ptempfile import TemporaryDirectory
 from calibre.utils.filenames import atomic_rename
@@ -60,9 +66,7 @@ def compiler():
 
     from calibre import walk
     from calibre.gui2 import must_use_qt
-    from calibre.utils.webengine import (
-        secure_webengine, setup_default_profile, setup_profile
-    )
+    from calibre.utils.webengine import secure_webengine, setup_default_profile, setup_profile
     must_use_qt()
     setup_default_profile()
 
@@ -346,20 +350,15 @@ def atomic_write(base, name, content):
 
 
 def run_rapydscript_tests():
-    from qt.core import QApplication, QByteArray, QEventLoop, QUrl
-    from qt.webengine import (
-        QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineUrlRequestJob,
-        QWebEngineUrlSchemeHandler
-    )
     from urllib.parse import parse_qs
 
+    from qt.core import QApplication, QByteArray, QEventLoop, QUrl
+    from qt.webengine import QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineUrlRequestJob, QWebEngineUrlSchemeHandler
+
     from calibre.constants import FAKE_HOST, FAKE_PROTOCOL
     from calibre.gui2 import must_use_qt
     from calibre.gui2.viewer.web_view import send_reply
-    from calibre.utils.webengine import (
-        create_script, insert_scripts, secure_webengine, setup_default_profile,
-        setup_fake_protocol, setup_profile
-    )
+    from calibre.utils.webengine import create_script, insert_scripts, secure_webengine, setup_default_profile, setup_fake_protocol, setup_profile
     must_use_qt()
     setup_fake_protocol()
     setup_default_profile()
diff --git a/src/calibre/utils/rcc/__init__.py b/src/calibre/utils/rcc/__init__.py
index 845ba9349e..b8ae07d7c0 100644
--- a/src/calibre/utils/rcc/__init__.py
+++ b/src/calibre/utils/rcc/__init__.py
@@ -1,10 +1,12 @@
 #!/usr/bin/env python
 # License: GPL v3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
 
-import os, io
+import io
+import os
 import sys
 import tempfile
 from posixpath import normpath
+
 from qt.core import QFile, QIODevice
 
 from calibre_extensions import rcc_backend
diff --git a/src/calibre/utils/recycle_bin.py b/src/calibre/utils/recycle_bin.py
index f688c1c3f2..ce91e6d09b 100644
--- a/src/calibre/utils/recycle_bin.py
+++ b/src/calibre/utils/recycle_bin.py
@@ -5,17 +5,20 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, shutil, time, sys
+import os
+import shutil
+import sys
+import time
 
 from calibre import isbytestring
-from calibre.constants import (iswindows, ismacos, filesystem_encoding,
-        islinux)
+from calibre.constants import filesystem_encoding, islinux, ismacos, iswindows
 
 recycle = None
 
 if iswindows:
-    from calibre.utils.ipc import eintr_retry_call
     from threading import Lock
+
+    from calibre.utils.ipc import eintr_retry_call
     from calibre_extensions import winutil
     recycler = None
     rlock = Lock()
diff --git a/src/calibre/utils/resources.py b/src/calibre/utils/resources.py
index d00343acc6..42132815cc 100644
--- a/src/calibre/utils/resources.py
+++ b/src/calibre/utils/resources.py
@@ -6,12 +6,12 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 
-import sys, os
+import os
+import sys
 
 from calibre import config_dir
 from polyglot.builtins import builtins
 
-
 user_dir = os.path.join(config_dir, 'resources')
 
 
diff --git a/src/calibre/utils/run_tests.py b/src/calibre/utils/run_tests.py
index e84252334a..39760bb90b 100644
--- a/src/calibre/utils/run_tests.py
+++ b/src/calibre/utils/run_tests.py
@@ -2,9 +2,13 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-import unittest, functools, importlib, importlib.resources, os
-from calibre.utils.monotonic import monotonic
+import functools
+import importlib
+import importlib.resources
+import os
+import unittest
 
+from calibre.utils.monotonic import monotonic
 
 is_ci = os.environ.get('CI', '').lower() == 'true'
 
@@ -85,9 +89,9 @@ def itertests(suite):
 
 
 def init_env():
-    from calibre.utils.config_base import reset_tweaks_to_default
     from calibre.ebooks.metadata.book.base import reset_field_metadata
     from calibre.ebooks.oeb.polish.utils import setup_css_parser_serialization
+    from calibre.utils.config_base import reset_tweaks_to_default
     reset_tweaks_to_default()
     reset_field_metadata()
     setup_css_parser_serialization()
@@ -172,7 +176,7 @@ class TestImports(unittest.TestCase):
         return count
 
     def test_import_of_all_python_modules(self):
-        from calibre.constants import iswindows, ismacos, islinux, isbsd
+        from calibre.constants import isbsd, islinux, ismacos, iswindows
         exclude_packages = {'calibre.devices.mtp.unix.upstream'}
         exclude_modules = set()
         if not iswindows:
diff --git a/src/calibre/utils/search_query_parser.py b/src/calibre/utils/search_query_parser.py
index c72615595f..e7b47940aa 100644
--- a/src/calibre/utils/search_query_parser.py
+++ b/src/calibre/utils/search_query_parser.py
@@ -17,16 +17,17 @@ methods :method:`SearchQueryParser.universal_set` and
 If this module is run, it will perform a series of unit tests.
 '''
 
-import weakref, re
+import re
+import weakref
 
-from calibre.constants import preferred_encoding
-from calibre.utils.icu import sort_key, lower as icu_lower
-from calibre.utils.localization import _
 from calibre import prints
+from calibre.constants import preferred_encoding
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import sort_key
+from calibre.utils.localization import _
 from polyglot.binary import as_hex_unicode, from_hex_unicode
 from polyglot.builtins import codepoint_to_chr
 
-
 '''
 This class manages access to the preference holding the saved search queries.
 It exists to ensure that unicode is used throughout, and also to permit
diff --git a/src/calibre/utils/search_query_parser_test.py b/src/calibre/utils/search_query_parser_test.py
index acfd90f2b1..91e515416b 100644
--- a/src/calibre/utils/search_query_parser_test.py
+++ b/src/calibre/utils/search_query_parser_test.py
@@ -5,7 +5,7 @@
 import operator
 import unittest
 
-from calibre.utils.search_query_parser import SearchQueryParser, Parser
+from calibre.utils.search_query_parser import Parser, SearchQueryParser
 
 
 class Tester(SearchQueryParser):
diff --git a/src/calibre/utils/serialize.py b/src/calibre/utils/serialize.py
index 707298df2e..81e187f0a5 100644
--- a/src/calibre/utils/serialize.py
+++ b/src/calibre/utils/serialize.py
@@ -25,9 +25,9 @@ def create_encoder(for_json=False):
         if isinstance(obj, (set, frozenset)):
             return encoded(1, tuple(obj), ExtType)
         if getattr(obj, '__calibre_serializable__', False):
+            from calibre.db.categories import Tag
             from calibre.ebooks.metadata.book.base import Metadata
             from calibre.library.field_metadata import FieldMetadata, fm_as_dict
-            from calibre.db.categories import Tag
             if isinstance(obj, Metadata):
                 from calibre.ebooks.metadata.book.serialize import metadata_as_dict
                 return encoded(
@@ -60,8 +60,8 @@ def json_dumps(data, **kw):
 
 
 def decode_metadata(x, for_json):
-    from polyglot.binary import from_base64_bytes
     from calibre.ebooks.metadata.book.serialize import metadata_from_dict
+    from polyglot.binary import from_base64_bytes
     obj = metadata_from_dict(x)
     if for_json and obj.cover_data and obj.cover_data[1]:
         obj.cover_data = obj.cover_data[0], from_base64_bytes(obj.cover_data[1])
diff --git a/src/calibre/utils/seven_zip.py b/src/calibre/utils/seven_zip.py
index 6cf16277f9..29263daf3f 100644
--- a/src/calibre/utils/seven_zip.py
+++ b/src/calibre/utils/seven_zip.py
@@ -55,6 +55,7 @@ def extract(path_or_stream, location):
 
 def test_basic():
     from tempfile import TemporaryDirectory
+
     from calibre import CurrentDir
 
     tdata = {
diff --git a/src/calibre/utils/shared_file.py b/src/calibre/utils/shared_file.py
index a2fef575cc..ea60f3c073 100644
--- a/src/calibre/utils/shared_file.py
+++ b/src/calibre/utils/shared_file.py
@@ -4,11 +4,11 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, sys
-
-from polyglot.builtins import reraise
+import os
+import sys
 
 from calibre.constants import iswindows
+from polyglot.builtins import reraise
 
 '''
 This module defines a share_open() function which is a replacement for
@@ -28,8 +28,9 @@ file before deleting it.
 '''
 
 if iswindows:
-    from numbers import Integral
     import msvcrt
+    from numbers import Integral
+
     from calibre_extensions import winutil
 
     _ACCESS_MASK = os.O_RDONLY | os.O_WRONLY | os.O_RDWR
@@ -103,6 +104,7 @@ else:
 
 def find_tests():
     import unittest
+
     from calibre.ptempfile import TemporaryDirectory
 
     class SharedFileTest(unittest.TestCase):
diff --git a/src/calibre/utils/shm.py b/src/calibre/utils/shm.py
index 0f1635af44..175f325c47 100644
--- a/src/calibre/utils/shm.py
+++ b/src/calibre/utils/shm.py
@@ -9,7 +9,8 @@ import secrets
 import stat
 import struct
 from typing import Optional, Union
-from calibre.constants import iswindows, ismacos
+
+from calibre.constants import ismacos, iswindows
 
 SHM_NAME_MAX = 30 if ismacos else 254
 if iswindows:
diff --git a/src/calibre/utils/short_uuid.py b/src/calibre/utils/short_uuid.py
index f97475c432..9b344e20b7 100644
--- a/src/calibre/utils/short_uuid.py
+++ b/src/calibre/utils/short_uuid.py
@@ -6,7 +6,9 @@
 Generate UUID encoded using a user specified alphabet.
 '''
 
-import string, math, uuid as _uuid
+import math
+import string
+import uuid as _uuid
 
 
 def num_to_string(number, alphabet, alphabet_len, pad_to_length=None):
diff --git a/src/calibre/utils/smtp.py b/src/calibre/utils/smtp.py
index 213ddbae47..01b697dbb1 100644
--- a/src/calibre/utils/smtp.py
+++ b/src/calibre/utils/smtp.py
@@ -8,7 +8,12 @@ This module implements a simple commandline SMTP client that supports:
   * Background delivery with failures being saved in a maildir mailbox
 '''
 
-import sys, traceback, os, socket, encodings.idna as idna
+import encodings.idna as idna
+import os
+import socket
+import sys
+import traceback
+
 from calibre import isbytestring
 from calibre.constants import iswindows
 from calibre.utils.localization import _
@@ -75,9 +80,9 @@ def create_mail(from_, to, subject, text=None, attachment_data=None,
                  attachment_type=None, attachment_name=None):
     assert text or attachment_data
 
+    import uuid
     from email.message import EmailMessage
     from email.utils import formatdate
-    import uuid
 
     outer = EmailMessage()
     outer['From'] = from_
@@ -117,6 +122,7 @@ def get_mx(host, verbose=0):
 def sendmail_direct(from_, to, msg, timeout, localhost, verbose,
         debug_output=None):
     from email.message import Message
+
     import polyglot.smtplib as smtplib
     hosts = get_mx(to.split('@')[-1].strip(), verbose)
     timeout=None  # Non blocking sockets sometimes don't work
diff --git a/src/calibre/utils/smtplib.py b/src/calibre/utils/smtplib.py
index 0db318ef6f..d1742b55ee 100644
--- a/src/calibre/utils/smtplib.py
+++ b/src/calibre/utils/smtplib.py
@@ -43,14 +43,14 @@ Example:
 #
 # This was modified from the Python 1.5 library HTTP lib.
 
-import socket
-import re
-import email.utils
 import base64
+import email.utils
 import hmac
+import re
+import socket
 from email.base64mime import body_encode as encode_base64
-from sys import stderr
 from functools import partial
+from sys import stderr
 
 from polyglot.builtins import string_or_bytes
 
diff --git a/src/calibre/utils/tdir_in_cache.py b/src/calibre/utils/tdir_in_cache.py
index 9672c36449..55c78ae470 100644
--- a/src/calibre/utils/tdir_in_cache.py
+++ b/src/calibre/utils/tdir_in_cache.py
@@ -36,6 +36,7 @@ if iswindows:
         return False
 else:
     import fcntl
+
     from calibre.utils.ipc import eintr_retry_call
 
     def lock_tdir(path):
diff --git a/src/calibre/utils/terminal.py b/src/calibre/utils/terminal.py
index cd31103b1e..6aee59ef56 100644
--- a/src/calibre/utils/terminal.py
+++ b/src/calibre/utils/terminal.py
@@ -4,10 +4,12 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import os, sys, re
+import os
+import re
+import sys
 
-from calibre.prints import is_binary
 from calibre.constants import iswindows
+from calibre.prints import is_binary
 from polyglot.builtins import iteritems
 
 if iswindows:
@@ -233,7 +235,9 @@ def windows_terminfo():
 
 
 def get_term_geometry():
-    import fcntl, termios, struct
+    import fcntl
+    import struct
+    import termios
 
     def ioctl_GWINSZ(fd):
         try:
diff --git a/src/calibre/utils/test_lock.py b/src/calibre/utils/test_lock.py
index 411ac63adf..5477ac0c55 100644
--- a/src/calibre/utils/test_lock.py
+++ b/src/calibre/utils/test_lock.py
@@ -13,10 +13,7 @@ from threading import Thread
 
 from calibre.constants import cache_dir, iswindows
 from calibre.utils.lock import ExclusiveFile, create_single_instance_mutex, unix_open
-from calibre.utils.tdir_in_cache import (
-    clean_tdirs_in, is_tdir_locked, retry_lock_tdir, tdir_in_cache, tdirs_in,
-    unlock_file
-)
+from calibre.utils.tdir_in_cache import clean_tdirs_in, is_tdir_locked, retry_lock_tdir, tdir_in_cache, tdirs_in, unlock_file
 from polyglot.builtins import iteritems, native_string_type
 
 
diff --git a/src/calibre/utils/threadpool.py b/src/calibre/utils/threadpool.py
index f5a7608c70..15c391eca0 100644
--- a/src/calibre/utils/threadpool.py
+++ b/src/calibre/utils/threadpool.py
@@ -47,6 +47,7 @@ __license__ = 'Python license'
 
 # standard library modules
 import threading
+
 from polyglot import queue
 
 # exceptions
diff --git a/src/calibre/utils/titlecase.py b/src/calibre/utils/titlecase.py
index f5d5163e04..6002fd12f5 100644
--- a/src/calibre/utils/titlecase.py
+++ b/src/calibre/utils/titlecase.py
@@ -10,7 +10,9 @@ License: http://www.opensource.org/licenses/mit-license.php
 
 import re
 
-from calibre.utils.icu import capitalize, lower as icu_lower, upper as icu_upper
+from calibre.utils.icu import capitalize
+from calibre.utils.icu import lower as icu_lower
+from calibre.utils.icu import upper as icu_upper
 
 __all__ = ['titlecase']
 __version__ = '0.5'
diff --git a/src/calibre/utils/unrar.py b/src/calibre/utils/unrar.py
index ebadbc8071..ff8100f6d8 100644
--- a/src/calibre/utils/unrar.py
+++ b/src/calibre/utils/unrar.py
@@ -6,8 +6,8 @@ __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import os
-import shutil
 import re
+import shutil
 from io import BytesIO
 
 from calibre.constants import filesystem_encoding, iswindows
@@ -112,7 +112,7 @@ def extract_first_alphabetically(stream):
 
 
 def extract_cover_image(stream):
-    from calibre.libunzip import sort_key, name_ok
+    from calibre.libunzip import name_ok, sort_key
     for name in sorted(names(stream), key=sort_key):
         if name_ok(name):
             return extract_member(stream, name=name, match=None)
diff --git a/src/calibre/utils/webengine.py b/src/calibre/utils/webengine.py
index 3234105ec5..2fd372b92a 100644
--- a/src/calibre/utils/webengine.py
+++ b/src/calibre/utils/webengine.py
@@ -4,14 +4,11 @@
 
 import json
 import os
-from qt.core import QBuffer, QIODevice, QObject, pyqtSignal, sip
-from qt.webengine import (
-    QWebEngineProfile, QWebEngineScript, QWebEngineSettings, QWebEngineUrlScheme
-)
 
-from calibre.constants import (
-    FAKE_PROTOCOL, SPECIAL_TITLE_FOR_WEBENGINE_COMMS, cache_dir
-)
+from qt.core import QBuffer, QIODevice, QObject, pyqtSignal, sip
+from qt.webengine import QWebEngineProfile, QWebEngineScript, QWebEngineSettings, QWebEngineUrlScheme
+
+from calibre.constants import FAKE_PROTOCOL, SPECIAL_TITLE_FOR_WEBENGINE_COMMS, cache_dir
 
 
 def setup_fake_protocol():
diff --git a/src/calibre/utils/windows/winsapi.py b/src/calibre/utils/windows/winsapi.py
index f808e9bb2a..efc865c2a0 100644
--- a/src/calibre/utils/windows/winsapi.py
+++ b/src/calibre/utils/windows/winsapi.py
@@ -10,8 +10,8 @@ def develop():
 
 
 def find_tests():
-    import unittest
     import os
+    import unittest
     is_ci = os.environ.get('CI', '').lower() == 'true'
 
     class TestSAPI(unittest.TestCase):
diff --git a/src/calibre/utils/windows/winspeech.py b/src/calibre/utils/windows/winspeech.py
index 5e7cc9acc5..0045361630 100644
--- a/src/calibre/utils/windows/winspeech.py
+++ b/src/calibre/utils/windows/winspeech.py
@@ -12,7 +12,7 @@ from itertools import count
 from queue import Empty, Queue
 from threading import Thread
 from time import monotonic
-from typing import NamedTuple, Tuple, Optional
+from typing import NamedTuple, Optional, Tuple
 
 from calibre.constants import DEBUG
 from calibre.utils.ipc.simple_worker import start_pipe_worker
diff --git a/src/calibre/utils/winreg/dde.py b/src/calibre/utils/winreg/dde.py
index 4a8c403e39..38c9fff5a9 100644
--- a/src/calibre/utils/winreg/dde.py
+++ b/src/calibre/utils/winreg/dde.py
@@ -5,7 +5,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import numbers
-from ctypes import POINTER, WINFUNCTYPE, c_void_p, c_ulong, c_char_p, windll, byref
+from ctypes import POINTER, WINFUNCTYPE, byref, c_char_p, c_ulong, c_void_p, windll
 from ctypes.wintypes import BOOL, DWORD, LPCWSTR, UINT
 
 from polyglot.builtins import itervalues
diff --git a/src/calibre/utils/winreg/lib.py b/src/calibre/utils/winreg/lib.py
index c39f222f74..c0cc018d29 100644
--- a/src/calibre/utils/winreg/lib.py
+++ b/src/calibre/utils/winreg/lib.py
@@ -4,7 +4,11 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import ctypes, ctypes.wintypes as types, struct, datetime, numbers
+import ctypes
+import ctypes.wintypes as types
+import datetime
+import numbers
+import struct
 
 from calibre_extensions import winutil
 
diff --git a/src/calibre/utils/wmf/__init__.py b/src/calibre/utils/wmf/__init__.py
index ff9972fa01..7a912414cd 100644
--- a/src/calibre/utils/wmf/__init__.py
+++ b/src/calibre/utils/wmf/__init__.py
@@ -60,7 +60,7 @@ def create_bmp_from_dib(raw):
 
 
 def to_png(bmp):
-    from qt.core import QImage, QByteArray, QBuffer, QIODevice
+    from qt.core import QBuffer, QByteArray, QImage, QIODevice
     i = QImage()
     if not i.loadFromData(bmp):
         raise ValueError('Invalid image data')
diff --git a/src/calibre/utils/wmf/emf.py b/src/calibre/utils/wmf/emf.py
index 51aa305eb6..7c5a7c9a05 100644
--- a/src/calibre/utils/wmf/emf.py
+++ b/src/calibre/utils/wmf/emf.py
@@ -5,8 +5,8 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
-from struct import unpack_from
 from collections import namedtuple
+from struct import unpack_from
 
 from calibre.utils.wmf import create_bmp_from_dib, to_png
 from polyglot.builtins import iteritems
diff --git a/src/calibre/utils/wmf/parse.py b/src/calibre/utils/wmf/parse.py
index 59b23cf53f..522ef4ad15 100644
--- a/src/calibre/utils/wmf/parse.py
+++ b/src/calibre/utils/wmf/parse.py
@@ -5,7 +5,8 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import sys, struct
+import struct
+import sys
 
 from calibre.utils.wmf import create_bmp_from_dib, to_png
 
diff --git a/src/calibre/utils/xml_parse.py b/src/calibre/utils/xml_parse.py
index 339538b900..fdd57dca75 100644
--- a/src/calibre/utils/xml_parse.py
+++ b/src/calibre/utils/xml_parse.py
@@ -42,7 +42,10 @@ def unsafe_xml_fromstring(string_or_bytes):
 
 
 def find_tests():
-    import unittest, tempfile, os
+    import os
+    import tempfile
+    import unittest
+
     from calibre.constants import iswindows
 
     class TestXMLParse(unittest.TestCase):
diff --git a/src/calibre/utils/zipfile.py b/src/calibre/utils/zipfile.py
index e493b75ccf..03c57bc7c6 100644
--- a/src/calibre/utils/zipfile.py
+++ b/src/calibre/utils/zipfile.py
@@ -17,7 +17,7 @@ from calibre import sanitize_file_name
 from calibre.constants import filesystem_encoding
 from calibre.ebooks.chardet import detect
 from calibre.ptempfile import SpooledTemporaryFile
-from polyglot.builtins import string_or_bytes, as_bytes
+from polyglot.builtins import as_bytes, string_or_bytes
 
 try:
     import zlib  # We may need its compression method
diff --git a/src/calibre/web/__init__.py b/src/calibre/web/__init__.py
index 4c4f3be0f4..50c0b76adf 100644
--- a/src/calibre/web/__init__.py
+++ b/src/calibre/web/__init__.py
@@ -39,9 +39,10 @@ def get_download_filename(url, cookie_file=None):
     Get a local filename for a URL using the content disposition header
     Returns empty string if an error occurs.
     '''
-    from calibre import browser
     from contextlib import closing
 
+    from calibre import browser
+
     filename = ''
 
     br = browser()
diff --git a/src/calibre/web/feeds/news.py b/src/calibre/web/feeds/news.py
index 60aaa71b6e..cb5c2a7669 100644
--- a/src/calibre/web/feeds/news.py
+++ b/src/calibre/web/feeds/news.py
@@ -16,10 +16,7 @@ from collections import defaultdict
 from contextlib import closing
 from urllib.parse import urlparse, urlsplit
 
-from calibre import (
-    __appname__, as_unicode, browser, force_unicode, iswindows, preferred_encoding,
-    random_user_agent, strftime,
-)
+from calibre import __appname__, as_unicode, browser, force_unicode, iswindows, preferred_encoding, random_user_agent, strftime
 from calibre.ebooks.BeautifulSoup import BeautifulSoup, CData, NavigableString, Tag
 from calibre.ebooks.metadata import MetaInformation
 from calibre.ebooks.metadata.opf2 import OPFCreator
@@ -33,9 +30,8 @@ from calibre.utils.logging import ThreadSafeWrapper
 from calibre.utils.threadpool import NoResultsPending, ThreadPool, WorkRequest
 from calibre.web import Recipe
 from calibre.web.feeds import Feed, feed_from_xml, feeds_from_index, templates
-from calibre.web.fetch.simple import (
-    AbortArticle, RecursiveFetcher, option_parser as web2disk_option_parser,
-)
+from calibre.web.fetch.simple import AbortArticle, RecursiveFetcher
+from calibre.web.fetch.simple import option_parser as web2disk_option_parser
 from calibre.web.fetch.utils import prepare_masthead_image
 from polyglot.builtins import string_or_bytes
 
diff --git a/src/calibre/web/feeds/recipes/__init__.py b/src/calibre/web/feeds/recipes/__init__.py
index 5e16423832..6a974a23fa 100644
--- a/src/calibre/web/feeds/recipes/__init__.py
+++ b/src/calibre/web/feeds/recipes/__init__.py
@@ -5,12 +5,14 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 '''
 Builtin recipes.
 '''
-import re, time, io
-from calibre.web.feeds.news import (BasicNewsRecipe, CustomIndexRecipe,
-    AutomaticNewsRecipe, CalibrePeriodical)
+import io
+import re
+import time
+
 from calibre.ebooks.BeautifulSoup import BeautifulSoup
 from calibre.utils.config import JSONConfig
-from polyglot.builtins import itervalues, codepoint_to_chr
+from calibre.web.feeds.news import AutomaticNewsRecipe, BasicNewsRecipe, CalibrePeriodical, CustomIndexRecipe
+from polyglot.builtins import codepoint_to_chr, itervalues
 
 basic_recipes = (BasicNewsRecipe, AutomaticNewsRecipe, CustomIndexRecipe,
         CalibrePeriodical)
diff --git a/src/calibre/web/feeds/recipes/collection.py b/src/calibre/web/feeds/recipes/collection.py
index 2ad02dca40..db0f84f98a 100644
--- a/src/calibre/web/feeds/recipes/collection.py
+++ b/src/calibre/web/feeds/recipes/collection.py
@@ -9,19 +9,19 @@ import calendar
 import os
 import zipfile
 from datetime import timedelta
+from threading import RLock
+
 from lxml import etree
 from lxml.builder import ElementMaker
-from threading import RLock
 
 from calibre import force_unicode
 from calibre.constants import numeric_version
-from calibre.utils.date import (
-    EPOCH, UNDEFINED_DATE, isoformat, local_tz, now as nowf, utcnow,
-)
+from calibre.utils.date import EPOCH, UNDEFINED_DATE, isoformat, local_tz, utcnow
+from calibre.utils.date import now as nowf
 from calibre.utils.iso8601 import parse_iso8601
-from calibre.utils.resources import get_path as P
 from calibre.utils.localization import _
 from calibre.utils.recycle_bin import delete_file
+from calibre.utils.resources import get_path as P
 from calibre.utils.xml_parse import safe_xml_fromstring
 from polyglot.builtins import iteritems
 
diff --git a/src/calibre/web/feeds/recipes/model.py b/src/calibre/web/feeds/recipes/model.py
index 25b8e0364b..3134db3a1c 100644
--- a/src/calibre/web/feeds/recipes/model.py
+++ b/src/calibre/web/feeds/recipes/model.py
@@ -4,20 +4,25 @@
 import copy
 import zipfile
 from functools import total_ordering
-from qt.core import (
-    QAbstractItemModel, QApplication, QFont, QIcon, QModelIndex, QPalette, QPixmap, Qt,
-    pyqtSignal,
-)
+
+from qt.core import QAbstractItemModel, QApplication, QFont, QIcon, QModelIndex, QPalette, QPixmap, Qt, pyqtSignal
 
 from calibre import force_unicode
 from calibre.utils.icu import primary_sort_key
-from calibre.utils.localization import _, get_language, countrycode_to_name
+from calibre.utils.localization import _, countrycode_to_name, get_language
 from calibre.utils.resources import get_path as P
 from calibre.utils.search_query_parser import ParseException, SearchQueryParser
 from calibre.web.feeds.recipes.collection import (
-    SchedulerConfig, add_custom_recipe, add_custom_recipes, download_builtin_recipe,
-    get_builtin_recipe, get_builtin_recipe_collection, get_custom_recipe,
-    get_custom_recipe_collection, remove_custom_recipe, update_custom_recipe,
+    SchedulerConfig,
+    add_custom_recipe,
+    add_custom_recipes,
+    download_builtin_recipe,
+    get_builtin_recipe,
+    get_builtin_recipe_collection,
+    get_custom_recipe,
+    get_custom_recipe_collection,
+    remove_custom_recipe,
+    update_custom_recipe,
     update_custom_recipes,
 )
 from polyglot.builtins import iteritems
diff --git a/src/calibre/web/feeds/templates.py b/src/calibre/web/feeds/templates.py
index 6c7f9daa00..524ae9222b 100644
--- a/src/calibre/web/feeds/templates.py
+++ b/src/calibre/web/feeds/templates.py
@@ -7,12 +7,11 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import copy
 
-from lxml import html, etree
-from lxml.html.builder import HTML, HEAD, TITLE, STYLE, DIV, BODY, \
-        STRONG, BR, SPAN, A, HR, UL, LI, H2, H3, IMG, P as PT, \
-        TABLE, TD, TR
+from lxml import etree, html
+from lxml.html.builder import BODY, BR, DIV, H2, H3, HEAD, HR, HTML, IMG, LI, SPAN, STRONG, STYLE, TABLE, TD, TITLE, TR, UL, A
+from lxml.html.builder import P as PT
 
-from calibre import strftime, isbytestring
+from calibre import isbytestring, strftime
 from calibre.utils.localization import _
 
 
diff --git a/src/calibre/web/fetch/simple.py b/src/calibre/web/fetch/simple.py
index 050e6dd36c..32466e35cf 100644
--- a/src/calibre/web/fetch/simple.py
+++ b/src/calibre/web/fetch/simple.py
@@ -30,10 +30,7 @@ from calibre.utils.localization import _
 from calibre.utils.logging import Log
 from calibre.web.fetch.utils import rescale_image
 from polyglot.http_client import responses
-from polyglot.urllib import (
-    URLError, quote, url2pathname, urljoin, urlparse, urlsplit, urlunparse,
-    urlunsplit
-)
+from polyglot.urllib import URLError, quote, url2pathname, urljoin, urlparse, urlsplit, urlunparse, urlunsplit
 
 
 class AbortArticle(Exception):
diff --git a/src/calibre/web/fetch/utils.py b/src/calibre/web/fetch/utils.py
index 4dab35c2ad..5981ddcd9d 100644
--- a/src/calibre/web/fetch/utils.py
+++ b/src/calibre/web/fetch/utils.py
@@ -2,7 +2,7 @@
 # License: GPLv3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from calibre.utils.img import image_from_data, scale_image, image_to_data, blend_on_canvas
+from calibre.utils.img import blend_on_canvas, image_from_data, image_to_data, scale_image
 
 
 def rescale_image(data, scale_news_images, compress_news_images_max_size, compress_news_images_auto_size):
diff --git a/src/css_selectors/__init__.py b/src/css_selectors/__init__.py
index 88ce09a151..ac78aee2ec 100644
--- a/src/css_selectors/__init__.py
+++ b/src/css_selectors/__init__.py
@@ -5,8 +5,8 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
+from css_selectors.errors import ExpressionError, SelectorError, SelectorSyntaxError
 from css_selectors.parser import parse
-from css_selectors.select import Select, INAPPROPRIATE_PSEUDO_CLASSES
-from css_selectors.errors import SelectorError, SelectorSyntaxError, ExpressionError
+from css_selectors.select import INAPPROPRIATE_PSEUDO_CLASSES, Select
 
 __all__ = ['parse', 'Select', 'INAPPROPRIATE_PSEUDO_CLASSES', 'SelectorError', 'SelectorSyntaxError', 'ExpressionError']
diff --git a/src/css_selectors/ordered_set.py b/src/css_selectors/ordered_set.py
index 51c30c2eb2..c2fc230cba 100644
--- a/src/css_selectors/ordered_set.py
+++ b/src/css_selectors/ordered_set.py
@@ -6,6 +6,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import collections.abc
+
 from polyglot.builtins import string_or_bytes
 
 SLICE_ALL = slice(None)
diff --git a/src/css_selectors/parser.py b/src/css_selectors/parser.py
index 826799ab7c..e39ae949a2 100644
--- a/src/css_selectors/parser.py
+++ b/src/css_selectors/parser.py
@@ -9,14 +9,13 @@
 
 """
 
-import sys
-import re
 import operator
+import re
 import string
+import sys
 
-from css_selectors.errors import SelectorSyntaxError, ExpressionError
-from polyglot.builtins import unicode_type, codepoint_to_chr
-
+from css_selectors.errors import ExpressionError, SelectorSyntaxError
+from polyglot.builtins import codepoint_to_chr, unicode_type
 
 utab = {c:c+32 for c in range(ord(u'A'), ord(u'Z')+1)}
 
diff --git a/src/css_selectors/select.py b/src/css_selectors/select.py
index 5fb6428a22..00ec9c1cd1 100644
--- a/src/css_selectors/select.py
+++ b/src/css_selectors/select.py
@@ -5,7 +5,8 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import re, itertools
+import itertools
+import re
 from collections import OrderedDict, defaultdict
 from functools import wraps
 from itertools import chain
@@ -13,9 +14,8 @@ from itertools import chain
 from lxml import etree
 
 from css_selectors.errors import ExpressionError
-from css_selectors.parser import parse, ascii_lower, Element, FunctionalPseudoElement
 from css_selectors.ordered_set import OrderedSet
-
+from css_selectors.parser import Element, FunctionalPseudoElement, ascii_lower, parse
 from polyglot.builtins import iteritems, itervalues
 
 PARSE_CACHE_SIZE = 200
diff --git a/src/css_selectors/tests.py b/src/css_selectors/tests.py
index e07c6cbcfe..d0b99ba40e 100644
--- a/src/css_selectors/tests.py
+++ b/src/css_selectors/tests.py
@@ -5,12 +5,14 @@
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import unittest, sys, argparse
+import argparse
+import sys
+import unittest
 
 from lxml import etree, html
 
-from css_selectors.errors import SelectorSyntaxError, ExpressionError
-from css_selectors.parser import tokenize, parse
+from css_selectors.errors import ExpressionError, SelectorSyntaxError
+from css_selectors.parser import parse, tokenize
 from css_selectors.select import Select
 
 
diff --git a/src/odf/anim.py b/src/odf/anim.py
index 705dd49f68..c51a5a798b 100644
--- a/src/odf/anim.py
+++ b/src/odf/anim.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import ANIMNS
 from .element import Element
+from .namespaces import ANIMNS
 
 
 # Autogenerated
diff --git a/src/odf/attrconverters.py b/src/odf/attrconverters.py
index 853a728fa9..1687bff05f 100644
--- a/src/odf/attrconverters.py
+++ b/src/odf/attrconverters.py
@@ -19,13 +19,31 @@
 
 import re
 
-from .namespaces import (
-    ANIMNS, CHARTNS, CONFIGNS, DR3DNS, DRAWNS, FONS, FORMNS, MANIFESTNS, METANS,
-    NUMBERNS, OFFICENS, PRESENTATIONNS, SCRIPTNS, SMILNS, STYLENS, SVGNS, TABLENS,
-    TEXTNS, XFORMSNS, XLINKNS
-)
 from polyglot.builtins import string_or_bytes, unicode_type
 
+from .namespaces import (
+    ANIMNS,
+    CHARTNS,
+    CONFIGNS,
+    DR3DNS,
+    DRAWNS,
+    FONS,
+    FORMNS,
+    MANIFESTNS,
+    METANS,
+    NUMBERNS,
+    OFFICENS,
+    PRESENTATIONNS,
+    SCRIPTNS,
+    SMILNS,
+    STYLENS,
+    SVGNS,
+    TABLENS,
+    TEXTNS,
+    XFORMSNS,
+    XLINKNS,
+)
+
 pattern_color =  re.compile(r'#[0-9a-fA-F]{6}')
 pattern_vector3D = re.compile(r'\([ ]*-?([0-9]+(\.[0-9]*)?|\.[0-9]+)([ ]+-?([0-9]+(\.[0-9]*)?|\.[0-9]+)){2}[ ]*\)')
 
diff --git a/src/odf/chart.py b/src/odf/chart.py
index 779d4ff3e5..6d507c39a6 100644
--- a/src/odf/chart.py
+++ b/src/odf/chart.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import CHARTNS
 from .element import Element
+from .namespaces import CHARTNS
 
 # Autogenerated
 
diff --git a/src/odf/config.py b/src/odf/config.py
index 1bb0228a24..03fb16e5a8 100644
--- a/src/odf/config.py
+++ b/src/odf/config.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import CONFIGNS
 from .element import Element
+from .namespaces import CONFIGNS
 
 # Autogenerated
 
diff --git a/src/odf/dc.py b/src/odf/dc.py
index d72bbff216..55fdc5f9ac 100644
--- a/src/odf/dc.py
+++ b/src/odf/dc.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import DCNS
 from .element import Element
+from .namespaces import DCNS
 
 # Autogenerated
 
diff --git a/src/odf/dr3d.py b/src/odf/dr3d.py
index 21a93928cd..6260223ec9 100644
--- a/src/odf/dr3d.py
+++ b/src/odf/dr3d.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import DR3DNS
 from .draw import StyleRefElement
+from .namespaces import DR3DNS
 
 # Autogenerated
 
diff --git a/src/odf/draw.py b/src/odf/draw.py
index 6fe6cdf284..9708fb34ad 100644
--- a/src/odf/draw.py
+++ b/src/odf/draw.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import DRAWNS, STYLENS, PRESENTATIONNS
 from .element import Element
+from .namespaces import DRAWNS, PRESENTATIONNS, STYLENS
 
 
 def StyleRefElement(stylename=None, classnames=None, **args):
diff --git a/src/odf/easyliststyle.py b/src/odf/easyliststyle.py
index f8126bea63..11a2b8de05 100644
--- a/src/odf/easyliststyle.py
+++ b/src/odf/easyliststyle.py
@@ -20,10 +20,12 @@
 
 
 import re
-from .style import ListLevelProperties
-from .text import ListStyle,ListLevelStyleNumber,ListLevelStyleBullet
+
 from polyglot.builtins import unicode_type
 
+from .style import ListLevelProperties
+from .text import ListLevelStyleBullet, ListLevelStyleNumber, ListStyle
+
 """
 Create a <text:list-style> element from a string or array.
 
diff --git a/src/odf/element.py b/src/odf/element.py
index fd2fb5f098..99b77e83a7 100644
--- a/src/odf/element.py
+++ b/src/odf/element.py
@@ -23,13 +23,14 @@
 #
 
 import xml.dom
-from xml.dom.minicompat import defproperty, EmptyNodeList
-from .namespaces import nsdict
-from . import grammar
-from .attrconverters import AttrConverters
+from xml.dom.minicompat import EmptyNodeList, defproperty
 
 from polyglot.builtins import unicode_type
 
+from . import grammar
+from .attrconverters import AttrConverters
+from .namespaces import nsdict
+
 # The following code is pasted form xml.sax.saxutils
 # Tt makes it possible to run the code without the xml sax package installed
 # To make it possible to have <rubbish> in your text elements, it is necessary to escape the texts
diff --git a/src/odf/elementtypes.py b/src/odf/elementtypes.py
index bb7c7fac1c..5eaee93cb1 100644
--- a/src/odf/elementtypes.py
+++ b/src/odf/elementtypes.py
@@ -20,8 +20,21 @@
 
 
 from .namespaces import (
-    ANIMNS, CHARTNS, DR3DNS, DRAWNS, FORMNS, MANIFESTNS, METANS, NUMBERNS, OFFICENS,
-    PRESENTATIONNS, SCRIPTNS, STYLENS, SVGNS, TABLENS, TEXTNS
+    ANIMNS,
+    CHARTNS,
+    DR3DNS,
+    DRAWNS,
+    FORMNS,
+    MANIFESTNS,
+    METANS,
+    NUMBERNS,
+    OFFICENS,
+    PRESENTATIONNS,
+    SCRIPTNS,
+    STYLENS,
+    SVGNS,
+    TABLENS,
+    TEXTNS,
 )
 
 # Inline element don't cause a box
diff --git a/src/odf/form.py b/src/odf/form.py
index 1980e522ed..275dac0fc7 100644
--- a/src/odf/form.py
+++ b/src/odf/form.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import FORMNS
 from .element import Element
+from .namespaces import FORMNS
 
 
 # Autogenerated
diff --git a/src/odf/grammar.py b/src/odf/grammar.py
index e8ac805106..44584a5f76 100644
--- a/src/odf/grammar.py
+++ b/src/odf/grammar.py
@@ -24,9 +24,28 @@ To be used for validation check in the API
 """
 
 from .namespaces import (
-    ANIMNS, CHARTNS, CONFIGNS, DCNS, DR3DNS, DRAWNS, FORMNS, MANIFESTNS, MATHNS,
-    METANS, NUMBERNS, OFFICENS, PRESENTATIONNS, SCRIPTNS, STYLENS, SVGNS, TABLENS,
-    TEXTNS, XFORMSNS, XLINKNS, SMILNS, FONS
+    ANIMNS,
+    CHARTNS,
+    CONFIGNS,
+    DCNS,
+    DR3DNS,
+    DRAWNS,
+    FONS,
+    FORMNS,
+    MANIFESTNS,
+    MATHNS,
+    METANS,
+    NUMBERNS,
+    OFFICENS,
+    PRESENTATIONNS,
+    SCRIPTNS,
+    SMILNS,
+    STYLENS,
+    SVGNS,
+    TABLENS,
+    TEXTNS,
+    XFORMSNS,
+    XLINKNS,
 )
 
 # The following code is generated from the RelaxNG schema with this notice:
diff --git a/src/odf/load.py b/src/odf/load.py
index a7b192debf..42b3e1793a 100644
--- a/src/odf/load.py
+++ b/src/odf/load.py
@@ -25,6 +25,7 @@
 
 
 from xml.sax import handler
+
 from .element import Element
 from .namespaces import OFFICENS
 
diff --git a/src/odf/manifest.py b/src/odf/manifest.py
index b3386478c4..4765fb9b75 100644
--- a/src/odf/manifest.py
+++ b/src/odf/manifest.py
@@ -20,8 +20,8 @@
 #
 
 
-from .namespaces import MANIFESTNS
 from .element import Element
+from .namespaces import MANIFESTNS
 
 # Autogenerated
 
diff --git a/src/odf/math.py b/src/odf/math.py
index 93362754f1..08245b3ccf 100644
--- a/src/odf/math.py
+++ b/src/odf/math.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import MATHNS
 from .element import Element
+from .namespaces import MATHNS
 
 # ODF 1.0 section 12.5
 # Mathematical content is represented by MathML 2.0
diff --git a/src/odf/meta.py b/src/odf/meta.py
index da49c499bd..89e500c7a5 100644
--- a/src/odf/meta.py
+++ b/src/odf/meta.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import METANS
 from .element import Element
+from .namespaces import METANS
 
 # Autogenerated
 
diff --git a/src/odf/number.py b/src/odf/number.py
index df157d7319..ed2c517d04 100644
--- a/src/odf/number.py
+++ b/src/odf/number.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import NUMBERNS
 from .element import Element
+from .namespaces import NUMBERNS
 from .style import StyleElement
 
 
diff --git a/src/odf/odf2moinmoin.py b/src/odf/odf2moinmoin.py
index ca6f699531..83ce1e71a0 100644
--- a/src/odf/odf2moinmoin.py
+++ b/src/odf/odf2moinmoin.py
@@ -20,11 +20,14 @@
 #
 
 
-import zipfile, xml.dom.minidom
-from .namespaces import nsdict
-from .elementtypes import empty_elements, inline_elements
+import xml.dom.minidom
+import zipfile
+
 from polyglot.builtins import unicode_type
 
+from .elementtypes import empty_elements, inline_elements
+from .namespaces import nsdict
+
 IGNORED_TAGS = [
     'draw:a'
     'draw:g',
diff --git a/src/odf/odf2xhtml.py b/src/odf/odf2xhtml.py
index 92f0066664..d889e02f88 100644
--- a/src/odf/odf2xhtml.py
+++ b/src/odf/odf2xhtml.py
@@ -21,17 +21,36 @@
 # pdb.set_trace()
 
 from collections import defaultdict
+from xml.dom import Node
 from xml.sax import handler
 from xml.sax.saxutils import escape, quoteattr
-from xml.dom import Node
 
-from .opendocument import load
-
-from .namespaces import ANIMNS, CHARTNS, CONFIGNS, DCNS, DR3DNS, DRAWNS, FONS, \
-  FORMNS, MATHNS, METANS, NUMBERNS, OFFICENS, PRESENTATIONNS, SCRIPTNS, \
-  SMILNS, STYLENS, SVGNS, TABLENS, TEXTNS, XLINKNS
 from polyglot.builtins import unicode_type
 
+from .namespaces import (
+    ANIMNS,
+    CHARTNS,
+    CONFIGNS,
+    DCNS,
+    DR3DNS,
+    DRAWNS,
+    FONS,
+    FORMNS,
+    MATHNS,
+    METANS,
+    NUMBERNS,
+    OFFICENS,
+    PRESENTATIONNS,
+    SCRIPTNS,
+    SMILNS,
+    STYLENS,
+    SVGNS,
+    TABLENS,
+    TEXTNS,
+    XLINKNS,
+)
+from .opendocument import load
+
 if False:  # Added by Kovid
     DR3DNS, MATHNS, CHARTNS, CONFIGNS, ANIMNS, FORMNS, SMILNS, SCRIPTNS
 
diff --git a/src/odf/odfmanifest.py b/src/odf/odfmanifest.py
index 403ed52b52..14986e5c67 100644
--- a/src/odf/odfmanifest.py
+++ b/src/odf/odfmanifest.py
@@ -20,10 +20,10 @@
 
 # This script lists the content of the manifest.xml file
 
-import zipfile
-from xml.sax import make_parser,handler
-from xml.sax.xmlreader import InputSource
 import io
+import zipfile
+from xml.sax import handler, make_parser
+from xml.sax.xmlreader import InputSource
 
 MANIFESTNS="urn:oasis:names:tc:opendocument:xmlns:manifest:1.0"
 
diff --git a/src/odf/office.py b/src/odf/office.py
index 99385a3d07..41a9330404 100644
--- a/src/odf/office.py
+++ b/src/odf/office.py
@@ -18,9 +18,9 @@
 #
 
 
-from .namespaces import OFFICENS
-from .element import Element
 from .draw import StyleRefElement
+from .element import Element
+from .namespaces import OFFICENS
 
 # Autogenerated
 
diff --git a/src/odf/opendocument.py b/src/odf/opendocument.py
index 25f711cd56..3bf3a4f25c 100644
--- a/src/odf/opendocument.py
+++ b/src/odf/opendocument.py
@@ -27,20 +27,33 @@ import zipfile
 from io import BytesIO
 from xml.sax.xmlreader import InputSource
 
-from polyglot.io import PolyglotBytesIO, PolyglotStringIO
 from polyglot.builtins import unicode_type
+from polyglot.io import PolyglotBytesIO, PolyglotStringIO
 
 from . import element, manifest, meta
 from .attrconverters import make_NCName
-from .namespaces import (
-    CHARTNS, DRAWNS, METANS, OFFICENS, PRESENTATIONNS, STYLENS, TABLENS, TEXTNS,
-    TOOLSVERSION
-)
+from .namespaces import CHARTNS, DRAWNS, METANS, OFFICENS, PRESENTATIONNS, STYLENS, TABLENS, TEXTNS, TOOLSVERSION
 from .odfmanifest import manifestlist
 from .office import (
-    AutomaticStyles, Body, Chart, Document, DocumentContent, DocumentMeta,
-    DocumentSettings, DocumentStyles, Drawing, FontFaceDecls, Image, MasterStyles,
-    Meta, Presentation, Scripts, Settings, Spreadsheet, Styles, Text
+    AutomaticStyles,
+    Body,
+    Chart,
+    Document,
+    DocumentContent,
+    DocumentMeta,
+    DocumentSettings,
+    DocumentStyles,
+    Drawing,
+    FontFaceDecls,
+    Image,
+    MasterStyles,
+    Meta,
+    Presentation,
+    Scripts,
+    Settings,
+    Spreadsheet,
+    Styles,
+    Text,
 )
 
 __version__= TOOLSVERSION
@@ -607,8 +620,9 @@ def OpenDocumentTextMaster():
 
 
 def __loadxmlparts(z, manifest, doc, objectpath):
+    from xml.sax import handler, make_parser
+
     from .load import LoadParser
-    from xml.sax import make_parser, handler
 
     for xmlfile in (objectpath+'settings.xml', objectpath+'meta.xml', objectpath+'content.xml', objectpath+'styles.xml'):
         if xmlfile not in manifest:
diff --git a/src/odf/presentation.py b/src/odf/presentation.py
index 287a1d434b..44f6c0b0fe 100644
--- a/src/odf/presentation.py
+++ b/src/odf/presentation.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import PRESENTATIONNS
 from .element import Element
+from .namespaces import PRESENTATIONNS
 
 # ODF 1.0 section 9.6 and 9.7
 # Autogenerated
diff --git a/src/odf/script.py b/src/odf/script.py
index d49cfb571f..113a413dad 100644
--- a/src/odf/script.py
+++ b/src/odf/script.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import SCRIPTNS
 from .element import Element
+from .namespaces import SCRIPTNS
 
 # ODF 1.0 section 12.4.1
 # The <script:event-listener> element binds an event to a macro.
diff --git a/src/odf/style.py b/src/odf/style.py
index 3c1c97ef01..d9a2640642 100644
--- a/src/odf/style.py
+++ b/src/odf/style.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import STYLENS
 from .element import Element
+from .namespaces import STYLENS
 
 
 def StyleElement(**args):
diff --git a/src/odf/svg.py b/src/odf/svg.py
index d4bf3f87c7..3017b4ac08 100644
--- a/src/odf/svg.py
+++ b/src/odf/svg.py
@@ -18,9 +18,9 @@
 #
 
 
-from .namespaces import SVGNS
-from .element import Element
 from .draw import DrawElement
+from .element import Element
+from .namespaces import SVGNS
 
 # Autogenerated
 
diff --git a/src/odf/table.py b/src/odf/table.py
index 5bd8125fbc..6afb1f676d 100644
--- a/src/odf/table.py
+++ b/src/odf/table.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import TABLENS
 from .element import Element
+from .namespaces import TABLENS
 
 
 # Autogenerated
diff --git a/src/odf/teletype.py b/src/odf/teletype.py
index 154874c97d..0384bc734b 100644
--- a/src/odf/teletype.py
+++ b/src/odf/teletype.py
@@ -28,7 +28,7 @@ elements.  This module takes care of that problem.
 
 
 from .element import Node
-from .text import S,LineBreak,Tab
+from .text import LineBreak, S, Tab
 
 
 class WhitespaceText:
diff --git a/src/odf/text.py b/src/odf/text.py
index 10d7f8a304..38c12c103e 100644
--- a/src/odf/text.py
+++ b/src/odf/text.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import TEXTNS
 from .element import Element
+from .namespaces import TEXTNS
 from .style import StyleElement
 
 # Autogenerated
diff --git a/src/odf/userfield.py b/src/odf/userfield.py
index 83927e4feb..d9013e973b 100644
--- a/src/odf/userfield.py
+++ b/src/odf/userfield.py
@@ -24,9 +24,9 @@
 import sys
 import zipfile
 
-from odf.text import UserFieldDecl
 from odf.namespaces import OFFICENS
 from odf.opendocument import load
+from odf.text import UserFieldDecl
 
 OUTENCODING = "utf-8"
 
diff --git a/src/odf/xforms.py b/src/odf/xforms.py
index c5b16bb9b9..4baee3a315 100644
--- a/src/odf/xforms.py
+++ b/src/odf/xforms.py
@@ -18,8 +18,8 @@
 #
 
 
-from .namespaces import XFORMSNS
 from .element import Element
+from .namespaces import XFORMSNS
 
 # ODF 1.0 section 11.2
 # XForms is designed to be embedded in another XML format.
diff --git a/src/polyglot/html_entities.py b/src/polyglot/html_entities.py
index c396e54615..1b82ebc9f1 100644
--- a/src/polyglot/html_entities.py
+++ b/src/polyglot/html_entities.py
@@ -3,4 +3,5 @@
 # License: GPL v3 Copyright: 2019, Eli Schwartz <eschwartz@archlinux.org>
 
 from html.entities import name2codepoint
+
 name2codepoint
diff --git a/src/polyglot/http_client.py b/src/polyglot/http_client.py
index ebd2e6b868..c79366c97a 100644
--- a/src/polyglot/http_client.py
+++ b/src/polyglot/http_client.py
@@ -2,13 +2,35 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2019, Eli Schwartz <eschwartz@archlinux.org>
 
-from http.client import (responses, HTTPConnection, HTTPSConnection,
-        BAD_REQUEST, FOUND, FORBIDDEN, HTTP_VERSION_NOT_SUPPORTED,
-        INTERNAL_SERVER_ERROR, METHOD_NOT_ALLOWED, MOVED_PERMANENTLY,
-        NOT_FOUND, NOT_IMPLEMENTED, NOT_MODIFIED, OK, PARTIAL_CONTENT,
-        PRECONDITION_FAILED, REQUEST_ENTITY_TOO_LARGE, REQUEST_URI_TOO_LONG,
-        REQUESTED_RANGE_NOT_SATISFIABLE, REQUEST_TIMEOUT, SEE_OTHER,
-        SERVICE_UNAVAILABLE, UNAUTHORIZED, _CS_IDLE, _CS_REQ_SENT, PRECONDITION_REQUIRED, UNPROCESSABLE_ENTITY)
+from http.client import (
+    _CS_IDLE,
+    _CS_REQ_SENT,
+    BAD_REQUEST,
+    FORBIDDEN,
+    FOUND,
+    HTTP_VERSION_NOT_SUPPORTED,
+    INTERNAL_SERVER_ERROR,
+    METHOD_NOT_ALLOWED,
+    MOVED_PERMANENTLY,
+    NOT_FOUND,
+    NOT_IMPLEMENTED,
+    NOT_MODIFIED,
+    OK,
+    PARTIAL_CONTENT,
+    PRECONDITION_FAILED,
+    PRECONDITION_REQUIRED,
+    REQUEST_ENTITY_TOO_LARGE,
+    REQUEST_TIMEOUT,
+    REQUEST_URI_TOO_LONG,
+    REQUESTED_RANGE_NOT_SATISFIABLE,
+    SEE_OTHER,
+    SERVICE_UNAVAILABLE,
+    UNAUTHORIZED,
+    UNPROCESSABLE_ENTITY,
+    HTTPConnection,
+    HTTPSConnection,
+    responses,
+)
 
 if False:
     responses, HTTPConnection, HTTPSConnection, BAD_REQUEST, FOUND, FORBIDDEN, HTTP_VERSION_NOT_SUPPORTED, INTERNAL_SERVER_ERROR, METHOD_NOT_ALLOWED
diff --git a/src/polyglot/io.py b/src/polyglot/io.py
index 443d4a93ce..44f38a68e7 100644
--- a/src/polyglot/io.py
+++ b/src/polyglot/io.py
@@ -3,7 +3,7 @@
 # License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from io import StringIO, BytesIO
+from io import BytesIO, StringIO
 
 
 class PolyglotStringIO(StringIO):
diff --git a/src/polyglot/reprlib.py b/src/polyglot/reprlib.py
index d3e5869d7b..56a7f48207 100644
--- a/src/polyglot/reprlib.py
+++ b/src/polyglot/reprlib.py
@@ -3,4 +3,5 @@
 # License: GPL v3 Copyright: 2019, Eli Schwartz <eschwartz@archlinux.org>
 
 from reprlib import repr
+
 repr
diff --git a/src/qt/core.py b/src/qt/core.py
index ac1ad67a3f..9e6914c8a4 100644
--- a/src/qt/core.py
+++ b/src/qt/core.py
@@ -3,8 +3,8 @@
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 
+from .core_name_map import module_names, name_map
 from .loader import dynamic_load
-from .core_name_map import name_map, module_names
 
 already_imported = {}
 qt_modules = {}
diff --git a/src/qt/core.pyi b/src/qt/core.pyi
index c2682e08f8..fbac6b66d9 100644
--- a/src/qt/core.pyi
+++ b/src/qt/core.pyi
@@ -1,5 +1,6 @@
 # autogenerated by __main__.py do not edit
 import PyQt6.QtCore
+
 PYQT_VERSION = PyQt6.QtCore.PYQT_VERSION
 PYQT_VERSION_STR = PyQt6.QtCore.PYQT_VERSION_STR
 QAbstractAnimation = PyQt6.QtCore.QAbstractAnimation
@@ -213,6 +214,7 @@ qUnregisterResourceData = PyQt6.QtCore.qUnregisterResourceData
 qVersion = PyQt6.QtCore.qVersion
 qWarning = PyQt6.QtCore.qWarning
 import PyQt6.QtGui
+
 QAbstractFileIconProvider = PyQt6.QtGui.QAbstractFileIconProvider
 QAbstractTextDocumentLayout = PyQt6.QtGui.QAbstractTextDocumentLayout
 QAction = PyQt6.QtGui.QAction
@@ -396,6 +398,7 @@ qRgba64 = PyQt6.QtGui.qRgba64
 qUnpremultiply = PyQt6.QtGui.qUnpremultiply
 qt_set_sequence_auto_mnemonic = PyQt6.QtGui.qt_set_sequence_auto_mnemonic
 import PyQt6.QtWidgets
+
 QAbstractButton = PyQt6.QtWidgets.QAbstractButton
 QAbstractGraphicsShapeItem = PyQt6.QtWidgets.QAbstractGraphicsShapeItem
 QAbstractItemDelegate = PyQt6.QtWidgets.QAbstractItemDelegate
@@ -589,6 +592,7 @@ qDrawShadeRect = PyQt6.QtWidgets.qDrawShadeRect
 qDrawWinButton = PyQt6.QtWidgets.qDrawWinButton
 qDrawWinPanel = PyQt6.QtWidgets.qDrawWinPanel
 import PyQt6.QtNetwork
+
 QAbstractNetworkCache = PyQt6.QtNetwork.QAbstractNetworkCache
 QAbstractSocket = PyQt6.QtNetwork.QAbstractSocket
 QAuthenticator = PyQt6.QtNetwork.QAuthenticator
@@ -639,9 +643,11 @@ QTcpServer = PyQt6.QtNetwork.QTcpServer
 QTcpSocket = PyQt6.QtNetwork.QTcpSocket
 QUdpSocket = PyQt6.QtNetwork.QUdpSocket
 import PyQt6.QtSvg
+
 QSvgGenerator = PyQt6.QtSvg.QSvgGenerator
 QSvgRenderer = PyQt6.QtSvg.QSvgRenderer
 import PyQt6.QtPrintSupport
+
 QAbstractPrintDialog = PyQt6.QtPrintSupport.QAbstractPrintDialog
 QPageSetupDialog = PyQt6.QtPrintSupport.QPageSetupDialog
 QPrintDialog = PyQt6.QtPrintSupport.QPrintDialog
@@ -651,6 +657,7 @@ QPrintPreviewWidget = PyQt6.QtPrintSupport.QPrintPreviewWidget
 QPrinter = PyQt6.QtPrintSupport.QPrinter
 QPrinterInfo = PyQt6.QtPrintSupport.QPrinterInfo
 import PyQt6.QtOpenGL
+
 QAbstractOpenGLFunctions = PyQt6.QtOpenGL.QAbstractOpenGLFunctions
 QOpenGLBuffer = PyQt6.QtOpenGL.QOpenGLBuffer
 QOpenGLDebugLogger = PyQt6.QtOpenGL.QOpenGLDebugLogger
@@ -673,8 +680,10 @@ QOpenGLVersionProfile = PyQt6.QtOpenGL.QOpenGLVersionProfile
 QOpenGLVertexArrayObject = PyQt6.QtOpenGL.QOpenGLVertexArrayObject
 QOpenGLWindow = PyQt6.QtOpenGL.QOpenGLWindow
 import PyQt6.QtOpenGLWidgets
+
 QOpenGLWidget = PyQt6.QtOpenGLWidgets.QOpenGLWidget
 import PyQt6.QtQuick
+
 QNativeInterface = PyQt6.QtQuick.QNativeInterface
 QQuickAsyncImageProvider = PyQt6.QtQuick.QQuickAsyncImageProvider
 QQuickCloseEvent = PyQt6.QtQuick.QQuickCloseEvent
diff --git a/src/qt/dbus.py b/src/qt/dbus.py
index 3fb3f5dc3a..a00a6838c7 100644
--- a/src/qt/dbus.py
+++ b/src/qt/dbus.py
@@ -3,8 +3,8 @@
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 
+from .dbus_name_map import module_names, name_map
 from .loader import dynamic_load
-from .dbus_name_map import name_map, module_names
 
 already_imported = {}
 qt_modules = {}
diff --git a/src/qt/dbus.pyi b/src/qt/dbus.pyi
index f289d8c3b4..5b4abd0488 100644
--- a/src/qt/dbus.pyi
+++ b/src/qt/dbus.pyi
@@ -1,5 +1,6 @@
 # autogenerated by __main__.py do not edit
 import PyQt6.QtDBus
+
 QDBus = PyQt6.QtDBus.QDBus
 QDBusAbstractAdaptor = PyQt6.QtDBus.QDBusAbstractAdaptor
 QDBusAbstractInterface = PyQt6.QtDBus.QDBusAbstractInterface
diff --git a/src/qt/loader.py b/src/qt/loader.py
index 286625390c..49a210babe 100644
--- a/src/qt/loader.py
+++ b/src/qt/loader.py
@@ -2,8 +2,8 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
-from importlib import import_module
 import sys
+from importlib import import_module
 
 
 def dynamic_load(name, name_map, already_imported, qt_modules, module_names=()):
diff --git a/src/qt/webengine.py b/src/qt/webengine.py
index c1bb7d2175..a6966515b6 100644
--- a/src/qt/webengine.py
+++ b/src/qt/webengine.py
@@ -4,7 +4,7 @@
 
 
 from .loader import dynamic_load
-from .webengine_name_map import name_map, module_names
+from .webengine_name_map import module_names, name_map
 
 already_imported = {}
 qt_modules = {}
diff --git a/src/qt/webengine.pyi b/src/qt/webengine.pyi
index 0a5067b82c..61f2aeb387 100644
--- a/src/qt/webengine.pyi
+++ b/src/qt/webengine.pyi
@@ -1,5 +1,6 @@
 # autogenerated by __main__.py do not edit
 import PyQt6.QtWebEngineCore
+
 PYQT_WEBENGINE_VERSION = PyQt6.QtWebEngineCore.PYQT_WEBENGINE_VERSION
 PYQT_WEBENGINE_VERSION_STR = PyQt6.QtWebEngineCore.PYQT_WEBENGINE_VERSION_STR
 QWebEngineCertificateError = PyQt6.QtWebEngineCore.QWebEngineCertificateError
@@ -34,4 +35,5 @@ qWebEngineChromiumSecurityPatchVersion = PyQt6.QtWebEngineCore.qWebEngineChromiu
 qWebEngineChromiumVersion = PyQt6.QtWebEngineCore.qWebEngineChromiumVersion
 qWebEngineVersion = PyQt6.QtWebEngineCore.qWebEngineVersion
 import PyQt6.QtWebEngineWidgets
+
 QWebEngineView = PyQt6.QtWebEngineWidgets.QWebEngineView
\ No newline at end of file
diff --git a/src/templite/__init__.py b/src/templite/__init__.py
index f46e777f82..da5c72a6ed 100644
--- a/src/templite/__init__.py
+++ b/src/templite/__init__.py
@@ -25,10 +25,12 @@
 #       MA 02110-1301, USA.
 #
 
-import sys, re
+import re
+import sys
 
 from polyglot.builtins import unicode_type
 
+
 class Templite:
     auto_emit = re.compile('(^[\'\"])|(^[a-zA-Z0-9_\[\]\'\"]+$)')
 
diff --git a/src/tinycss/__init__.py b/src/tinycss/__init__.py
index 73451baf94..176a9ff8e5 100644
--- a/src/tinycss/__init__.py
+++ b/src/tinycss/__init__.py
@@ -10,13 +10,13 @@
 """
 
 from .version import VERSION
+
 __version__ = VERSION
 
 from tinycss.css21 import CSS21Parser
-from tinycss.page3 import CSSPage3Parser
 from tinycss.fonts3 import CSSFonts3Parser
 from tinycss.media3 import CSSMedia3Parser
-
+from tinycss.page3 import CSSPage3Parser
 
 PARSER_MODULES = {
     'page3': CSSPage3Parser,
diff --git a/src/tinycss/css21.py b/src/tinycss/css21.py
index 1ccd45cde0..d48953fb85 100644
--- a/src/tinycss/css21.py
+++ b/src/tinycss/css21.py
@@ -14,12 +14,9 @@
 from itertools import chain, islice
 
 from tinycss.decoding import decode
+from tinycss.parsing import ParseError, remove_whitespace, split_on_comma, strip_whitespace, validate_any, validate_value
 from tinycss.token_data import TokenList
 from tinycss.tokenizer import tokenize_grouped
-from tinycss.parsing import (
-    strip_whitespace, remove_whitespace, split_on_comma, validate_value,
-    validate_any, ParseError)
-
 
 #  stylesheet  : [ CDO | CDC | S | statement ]*;
 #  statement   : ruleset | at-rule;
diff --git a/src/tinycss/decoding.py b/src/tinycss/decoding.py
index 79717ff034..bdad7392d0 100644
--- a/src/tinycss/decoding.py
+++ b/src/tinycss/decoding.py
@@ -16,7 +16,6 @@ import re
 
 from polyglot.binary import from_hex_bytes
 
-
 __all__ = ['decode']  # Everything else is implementation detail
 
 
diff --git a/src/tinycss/fonts3.py b/src/tinycss/fonts3.py
index f592a66730..bb43c5e5e0 100644
--- a/src/tinycss/fonts3.py
+++ b/src/tinycss/fonts3.py
@@ -7,7 +7,9 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 
 import re
+
 from tinycss.css21 import CSS21Parser, ParseError
+
 from .tokenizer import tokenize_grouped
 
 
diff --git a/src/tinycss/media3.py b/src/tinycss/media3.py
index ee1f6a0a40..de18a3cd07 100644
--- a/src/tinycss/media3.py
+++ b/src/tinycss/media3.py
@@ -5,9 +5,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from tinycss.css21 import CSS21Parser
-from tinycss.parsing import remove_whitespace, split_on_comma, ParseError
 from polyglot.builtins import error_message
+from tinycss.css21 import CSS21Parser
+from tinycss.parsing import ParseError, remove_whitespace, split_on_comma
 
 
 class MediaQuery:
diff --git a/src/tinycss/tests/color3.py b/src/tinycss/tests/color3.py
index 81bc669dc1..05ff9f485e 100644
--- a/src/tinycss/tests/color3.py
+++ b/src/tinycss/tests/color3.py
@@ -5,7 +5,7 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from tinycss.color3 import parse_color_string, hsl_to_rgb
+from tinycss.color3 import hsl_to_rgb, parse_color_string
 from tinycss.tests import BaseTest
 
 
diff --git a/src/tinycss/tests/css21.py b/src/tinycss/tests/css21.py
index a570b26fcf..fd083e3b03 100644
--- a/src/tinycss/tests/css21.py
+++ b/src/tinycss/tests/css21.py
@@ -10,8 +10,9 @@ import os
 import tempfile
 
 from tinycss.css21 import CSS21Parser
-from tinycss.tests.tokenizing import jsonify
 from tinycss.tests import BaseTest
+from tinycss.tests.tokenizing import jsonify
+
 
 class CoreParser(CSS21Parser):
     """A parser that always accepts unparsed at-rules."""
diff --git a/src/tinycss/tests/decoding.py b/src/tinycss/tests/decoding.py
index 3ae4e5e156..79a1017994 100644
--- a/src/tinycss/tests/decoding.py
+++ b/src/tinycss/tests/decoding.py
@@ -8,6 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from tinycss.decoding import decode
 from tinycss.tests import BaseTest
 
+
 def params(css, encoding, use_bom=False, expect_error=False, **kwargs):
     """Nicer syntax to make a tuple."""
     return css, encoding, use_bom, expect_error, kwargs
diff --git a/src/tinycss/tests/fonts3.py b/src/tinycss/tests/fonts3.py
index 8f220c961f..a59429deca 100644
--- a/src/tinycss/tests/fonts3.py
+++ b/src/tinycss/tests/fonts3.py
@@ -5,10 +5,9 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from tinycss.fonts3 import CSSFonts3Parser, parse_font_family, parse_font, serialize_font
-from tinycss.tests import BaseTest
-
 from polyglot.builtins import iteritems
+from tinycss.fonts3 import CSSFonts3Parser, parse_font, parse_font_family, serialize_font
+from tinycss.tests import BaseTest
 
 
 class TestFonts3(BaseTest):
diff --git a/src/tinycss/tests/main.py b/src/tinycss/tests/main.py
index 364172080b..3e56cb27df 100644
--- a/src/tinycss/tests/main.py
+++ b/src/tinycss/tests/main.py
@@ -5,7 +5,8 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import unittest, argparse
+import argparse
+import unittest
 
 
 def find_tests():
diff --git a/src/tinycss/tests/media3.py b/src/tinycss/tests/media3.py
index af200f2492..92572c9cb4 100644
--- a/src/tinycss/tests/media3.py
+++ b/src/tinycss/tests/media3.py
@@ -5,9 +5,11 @@
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from tinycss.media3 import CSSMedia3Parser, MediaQuery as MQ
+from tinycss.media3 import CSSMedia3Parser
+from tinycss.media3 import MediaQuery as MQ
 from tinycss.tests import BaseTest, jsonify
 
+
 def jsonify_expr(e):
     if e is None:
         return None
diff --git a/src/tinycss/tests/page3.py b/src/tinycss/tests/page3.py
index 2387445a67..318ceb6bb7 100644
--- a/src/tinycss/tests/page3.py
+++ b/src/tinycss/tests/page3.py
@@ -8,6 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from tinycss.page3 import CSSPage3Parser
 from tinycss.tests import BaseTest
 
+
 class TestPage3(BaseTest):
 
     def test_selectors(self):
diff --git a/src/tinycss/tests/tokenizing.py b/src/tinycss/tests/tokenizing.py
index f9d6e8bbb5..de91735c54 100644
--- a/src/tinycss/tests/tokenizing.py
+++ b/src/tinycss/tests/tokenizing.py
@@ -6,7 +6,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from tinycss.tests import BaseTest, jsonify
-from tinycss.tokenizer import python_tokenize_flat, c_tokenize_flat, regroup
+from tinycss.tokenizer import c_tokenize_flat, python_tokenize_flat, regroup
 
 if c_tokenize_flat is None:
     tokenizers = (python_tokenize_flat,)
diff --git a/src/tinycss/token_data.py b/src/tinycss/token_data.py
index 5b78f49e88..30f6b9d72a 100644
--- a/src/tinycss/token_data.py
+++ b/src/tinycss/token_data.py
@@ -10,12 +10,11 @@
 """
 
 
-import re
-import sys
-import operator
 import functools
+import operator
+import re
 import string
-
+import sys
 
 # * Raw strings with the r'' notation are used so that \ do not need
 #   to be escaped.