code: def get_items_for_config_file_output(self, source_to_settings,
                                           parsed_namespace):
          
          config_file_items = OrderedDict()
          for source, settings in source_to_settings.items():
              if source == _COMMAND_LINE_SOURCE_KEY:
                  _, existing_command_line_args = settings['']
                  for action in self._actions:
                      config_file_keys = self.get_possible_config_keys(action)
                      if config_file_keys and not action.is_positional_arg and \
                          already_on_command_line(existing_command_line_args,
                                                  action.option_strings):
                          value = getattr(parsed_namespace, action.dest, None)
                          if value is not None:
                              if isinstance(value, bool):
                                  value = str(value).lower()
                              config_file_items[config_file_keys[0]] = value
  
              elif source == _ENV_VAR_SOURCE_KEY:
                  for key, (action, value) in settings.items():
                      config_file_keys = self.get_possible_config_keys(action)
                      if config_file_keys:
                          value = getattr(parsed_namespace, action.dest, None)
                          if value is not None:
                              config_file_items[config_file_keys[0]] = value
              elif source.startswith(_CONFIG_FILE_SOURCE_KEY):
                  for key, (action, value) in settings.items():
                      config_file_items[key] = value
              elif source == _DEFAULTS_SOURCE_KEY:
                  for key, (action, value) in settings.items():
                      config_file_keys = self.get_possible_config_keys(action)
                      if config_file_keys:
                          value = getattr(parsed_namespace, action.dest, None)
                          if value is not None:
                              config_file_items[config_file_keys[0]] = value
          return config_file_items
docs: Converts the given settings back to a dictionary that can be passed
          to ConfigFormatParser.serialize(..).
  
          Args:
              source_to_settings: the dictionary described in parse_known_args()
              parsed_namespace: namespace object created within parse_known_args()
          Returns:
              an OrderedDict where keys are strings and values are either strings
              or lists