diff --git a/src/calibre/db/tables.py b/src/calibre/db/tables.py
index c81cae5ce0..a373a291ac 100644
--- a/src/calibre/db/tables.py
+++ b/src/calibre/db/tables.py
@@ -10,12 +10,10 @@ import numbers
 from datetime import datetime, timedelta
 from collections import defaultdict
 
-from calibre.constants import plugins
 from calibre.utils.date import parse_date, UNDEFINED_DATE, utc_tz
 from calibre.ebooks.metadata import author_to_author_sort
 from polyglot.builtins import iteritems, itervalues, range
-
-_c_speedup = plugins['speedup'][0].parse_date
+from calibre_extensions.speedup import parse_date as _c_speedup
 
 
 def c_parse(val):
diff --git a/src/calibre/startup.py b/src/calibre/startup.py
index 571ad82753..751c984eca 100644
--- a/src/calibre/startup.py
+++ b/src/calibre/startup.py
@@ -20,7 +20,7 @@ builtins.__dict__['__'] = lambda s: s
 # For backwards compat with some third party plugins
 builtins.__dict__['dynamic_property'] = lambda func: func(None)
 
-from calibre.constants import iswindows, plugins, ismacos, islinux, DEBUG, isfreebsd
+from calibre.constants import iswindows, ismacos, islinux, DEBUG, isfreebsd
 
 
 def get_debug_executable():
@@ -149,6 +149,7 @@ def initialize_calibre():
         # Name all threads at the OS level created using the threading module, see
         # http://bugs.python.org/issue15500
         import threading
+        from calibre_extensions import speedup
 
         orig_start = threading.Thread.start
 
@@ -163,7 +164,7 @@ def initialize_calibre():
                 if name:
                     if isinstance(name, unicode_type):
                         name = name.encode('ascii', 'replace').decode('ascii')
-                    plugins['speedup'][0].set_thread_name(name[:15])
+                    speedup.set_thread_name(name[:15])
             except Exception:
                 pass  # Don't care about failure to set name
         threading.Thread.start = new_start
diff --git a/src/tinycss/token_data.py b/src/tinycss/token_data.py
index 3e070bae8c..c539eb1af6 100644
--- a/src/tinycss/token_data.py
+++ b/src/tinycss/token_data.py
@@ -186,6 +186,7 @@ def _init():
         for names in dispatch
     )
 
+
 _init()
 
 
@@ -196,6 +197,7 @@ def _unicode_replace(match, int=int, unichr=unichr, maxunicode=sys.maxunicode):
     else:
         return '\N{REPLACEMENT CHARACTER}'  # U+FFFD
 
+
 UNICODE_UNESCAPE = functools.partial(
     re.compile(COMPILED_MACROS['unicode'], re.I).sub,
     _unicode_replace)
@@ -204,12 +206,15 @@ NEWLINE_UNESCAPE = functools.partial(
     re.compile(r'()\\' + COMPILED_MACROS['nl']).sub,
     '')
 
+
 SIMPLE_UNESCAPE = functools.partial(
-    re.compile(r'\\(%s)' % COMPILED_MACROS['simple_escape'] , re.I).sub,
+    re.compile(r'\\(%s)' % COMPILED_MACROS['simple_escape'], re.I).sub,
     # Same as r'\1', but faster on CPython
     operator.methodcaller('group', 1))
 
-FIND_NEWLINES = lambda x : list(re.compile(COMPILED_MACROS['nl']).finditer(x))
+
+def FIND_NEWLINES(x):
+    return list(re.compile(COMPILED_MACROS['nl']).finditer(x))
 
 
 class Token(object):
@@ -439,11 +444,12 @@ class TokenList(list):
         """
         return ''.join(token.as_css() for token in self)
 
+
 def load_c_tokenizer():
-    from calibre.constants import plugins
-    tokenizer, err = plugins['tokenizer']
-    if err:
-        raise RuntimeError('Failed to load module tokenizer: %s' % err)
+    from calibre_extensions import tokenizer
     tokens = list(':;(){}[]') + ['DELIM', 'INTEGER', 'STRING']
-    tokenizer.init(COMPILED_TOKEN_REGEXPS, UNICODE_UNESCAPE, NEWLINE_UNESCAPE, SIMPLE_UNESCAPE, FIND_NEWLINES, TOKEN_DISPATCH, COMPILED_TOKEN_INDEXES, *tokens)
+    tokenizer.init(
+        COMPILED_TOKEN_REGEXPS, UNICODE_UNESCAPE, NEWLINE_UNESCAPE,
+        SIMPLE_UNESCAPE, FIND_NEWLINES, TOKEN_DISPATCH, COMPILED_TOKEN_INDEXES,
+        *tokens)
     return tokenizer