File "apitools/base/py/encoding.py", line 110, in DictToMessage
  return JsonToMessage(message_type, json.dumps(d))
File "apitools/base/py/encoding.py", line 104, in JsonToMessage
  return _ProtoJsonApiTools.Get().decode_message(message_type, message)
File "apitools/base/py/encoding.py", line 290, in decode_message
  message_type, result)
File "apitools/base/protorpclite/protojson.py", line 211, in decode_message
  message = self.__decode_dictionary(message_type, dictionary)
File "apitools/base/protorpclite/protojson.py", line 284, in __decode_dictionary
  for item in value]
File "apitools/base/py/encoding.py", line 312, in decode_field
  field.message_type, json.dumps(value))
File "apitools/base/py/encoding.py", line 290, in decode_message
  message_type, result)
File "apitools/base/protorpclite/protojson.py", line 211, in decode_message
  message = self.__decode_dictionary(message_type, dictionary)
File "apitools/base/protorpclite/protojson.py", line 262, in __decode_dictionary
  for key, value in six.iteritems(dictionary):
File "six/__init__.py", line 605, in iteritems
  return d.iteritems(**kw)