diff --git a/src/calibre/utils/config.py b/src/calibre/utils/config.py
index 7a47a76036..0c6ded74de 100644
--- a/src/calibre/utils/config.py
+++ b/src/calibre/utils/config.py
@@ -1,4 +1,4 @@
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function, unicode_literals
 
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
@@ -166,11 +166,11 @@ class OptionParser(optparse.OptionParser):
 
     def options_iter(self):
         for opt in self.option_list:
-            if str(opt).strip():
+            if native_string_type(opt).strip():
                 yield opt
         for gr in self.option_groups:
             for opt in gr.option_list:
-                if str(opt).strip():
+                if native_string_type(opt).strip():
                     yield opt
 
     def option_by_dest(self, dest):
diff --git a/src/calibre/utils/mem.py b/src/calibre/utils/mem.py
index 815f2d2e0b..f48e8c0510 100644
--- a/src/calibre/utils/mem.py
+++ b/src/calibre/utils/mem.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python2
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
+from __future__ import absolute_import, division, print_function, unicode_literals
 
-from __future__ import print_function
 __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
@@ -49,4 +49,3 @@ def diff_hists(h1, h2):
         if h1[k] != h2[k]:
             print("%s: %d -> %d (%s%d)" % (
                 k, h1[k], h2[k], h2[k] > h1[k] and "+" or "", h2[k] - h1[k]))
-
diff --git a/src/calibre/utils/resources.py b/src/calibre/utils/resources.py
index 2b380efc42..ea2e704d3c 100644
--- a/src/calibre/utils/resources.py
+++ b/src/calibre/utils/resources.py
@@ -1,7 +1,6 @@
 #!/usr/bin/env python2
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
-from __future__ import with_statement
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function, unicode_literals
 
 __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
@@ -85,7 +84,7 @@ def get_image_path(path, data=False, allow_user_override=True):
 
 
 def js_name_to_path(name, ext='.coffee'):
-    path = (u'/'.join(name.split('.'))) + ext
+    path = ('/'.join(name.split('.'))) + ext
     d = os.path.dirname
     base = d(d(os.path.abspath(__file__)))
     return os.path.join(base, path)