message: Add comments back in
diff: @@ -33,8 +33,11 @@ _VERSION = '1.4.0'
  REQUIRED_PACKAGES = [
  'absl-py',
  + # weakref.finalize introduced in Python 3.4
  'backports.weakref >= 1.0rc1; python_version < "3.4"',
  + # enum module introduced in Python 3.4
  'enum34 >= 1.1.6; python_version < "3.4"',
  + # Needed for unittest.mock in Python 2
  'mock >= 2.0.0; python_version < "3.0"',
  'numpy >= 1.12.1',
  'six >= 1.10.0',
  