Use tuple everywhere with explicit conversion.

presubmit_canned_checks.py

 # Copyright (c) 2010 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.
 
 """Generic presubmit checks that can be reused by other presubmit checks."""
 
 
 ### Description checks
 
 def CheckChangeHasTestField(input_api, output_api):
@@ skipping 558 matching lines @@
       if Find(filepath, white_list) and not Find(filepath, black_list):
         files.append(filepath)
   return files
 
 
 def RunPylint(input_api, output_api, white_list=None, black_list=None):
   """Run pylint on python files.
 
   The default white_list enforces looking only a *.py files.
   """
-  white_list = white_list or ['.*\.py$']
-  black_list = black_list or input_api.DEFAULT_BLACK_LIST
+  white_list = tuple(white_list or ('.*\.py$',))
+  black_list = tuple(black_list or input_api.DEFAULT_BLACK_LIST)
   if input_api.is_committing:
     error_type = output_api.PresubmitError
   else:
     error_type = output_api.PresubmitPromptWarning
 
   # Only trigger if there is at least one python file affected.
   src_filter = lambda x: input_api.FilterSourceFile(x, white_list, black_list)
   if not input_api.AffectedSourceFiles(src_filter):
     return []
 
@@ skipping 248 matching lines @@
   Args:
     input_api: Bag of input related interfaces.
     output_api: Bag of output related interfaces.
     excluded_paths: Don't include these paths in common checks.
     text_files: Which file are to be treated as documentation text files.
     license_header: What license header should be on files.
     project_name: What is the name of the project as it appears in the license.
   Returns:
     A list of warning or error objects.
   """
-  excluded_paths = excluded_paths or  tuple()
-  text_files = text_files or (
+  excluded_paths = tuple(excluded_paths or [])
+  text_files = tuple(text_files or (
       r'.+\.txt$',
       r'.+\.json$',
-  )
+  ))
   project_name = project_name or 'Chromium'
   license_header = license_header or (
       r'.*? Copyright \(c\) %(year)s The %(project)s Authors\. '
         r'All rights reserved\.\n'
       r'.*? Use of this source code is governed by a BSD-style license that '
         r'can be\n'
       r'.*? found in the LICENSE file\.\n'
   ) % {
       'year': input_api.time.strftime('%Y'),
       'project': project_name,
@@ skipping 48 matching lines @@
     results.extend(input_api.canned_checks.CheckChangeSvnEolStyle(
         input_api, output_api, source_file_filter=text_files))
     snapshot("checking svn mime types")
     results.extend(input_api.canned_checks.CheckSvnForCommonMimeTypes(
         input_api, output_api))
     snapshot("checking license")
     results.extend(input_api.canned_checks.CheckLicense(
         input_api, output_api, license_header, source_file_filter=sources))
   snapshot("done")
   return results