Cleanup pylint errors

pylib/gyp/generator/xcode.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import filecmp
 import gyp.common
 import gyp.xcodeproj_file
 import gyp.xcode_ninja
 import errno
 import os
@@ skipping 504 matching lines @@
   xct.ResourcesPhase().AddFile(resource)
 
 
 def AddHeaderToTarget(header, pbxp, xct, is_public):
   # TODO(mark): Combine with AddSourceToTarget above?  Or just inline this call
   # where it's used.
   settings = '{ATTRIBUTES = (%s, ); }' % ('Private', 'Public')[is_public]
   xct.HeadersPhase().AddFile(header, settings)
 
 
-_xcode_variable_re = re.compile('(\$\((.*?)\))')
+_xcode_variable_re = re.compile(r'(\$\((.*?)\))')
 def ExpandXcodeVariables(string, expansions):
   """Expands Xcode-style $(VARIABLES) in string per the expansions dict.
 
   In some rare cases, it is appropriate to expand Xcode variables when a
   project file is generated.  For any substring $(VAR) in string, if VAR is a
   key in the expansions dict, $(VAR) will be replaced with expansions[VAR].
   Any $(VAR) substring in string for which VAR is not a key in the expansions
   dict will remain in the returned string.
   """
 
@@ skipping 698 matching lines @@
 
   for build_file in build_files:
     xcode_projects[build_file].Finalize1(xcode_targets, serialize_all_tests)
 
   for build_file in build_files:
     xcode_projects[build_file].Finalize2(xcode_targets,
                                          xcode_target_to_target_dict)
 
   for build_file in build_files:
     xcode_projects[build_file].Write()