Switch from {...} to dict((...)) generator syntax. The former doesn't work in

chrome/common/extensions/docs/server2/caching_rietveld_patcher.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from datetime import datetime, timedelta
 from file_system import FileNotFoundError, ToUnicode
 from future import Future
 from patcher import Patcher
 
 _VERSION_CACHE_MAXAGE = timedelta(seconds=5)
 
 ''' Append @version for keys to distinguish between different patchsets of
 an issue.
 '''
 def _MakeKey(path, version):
   return '%s@%s' % (path, version)
 
 def _ToObjectStoreValue(raw_value, version):
-  return {_MakeKey(key, version): raw_value[key] for key in raw_value}
+  return dict((_MakeKey(key, version), raw_value[key])
+              for key in raw_value)
 
 def _FromObjectStoreValue(raw_value, binary):
-  return {key[0:key.rfind('@')]: _HandleBinary(raw_value[key], binary)
-          for key in raw_value}
+  return dict((key[0:key.rfind('@')], _HandleBinary(raw_value[key], binary))
+              for key in raw_value)
 
 def _HandleBinary(data, binary):
   return data if binary else ToUnicode(data)
 
 class _AsyncUncachedFuture(object):
   def __init__(self,
                version,
                paths,
                binary,
                cached_value,
@@ skipping 82 matching lines @@
     return _AsyncUncachedFuture(version,
                                 paths,
                                 binary,
                                 cached_value,
                                 missing_paths,
                                 self._patcher.Apply(set(added) | set(modified),
                                                     None,
                                                     True,
                                                     version),
                                 self._file_object_store)