def _list(self, request, start_response):
configs = []<EOL>generator = directory_list_generator.DirectoryListGenerator(request)<EOL>for config in self._config_manager.configs.itervalues():<EOL><INDENT>if config != self.API_CONFIG:<EOL><INDENT>configs.append(config)<EOL><DEDENT><DEDENT>directory = generator.pretty_print_config_to_json(configs)<EOL>if not directory:<EOL><INDENT>_logger.error('<STR_LIT>')<EOL>return util.send_wsgi_not_found_response(start_response)<EOL><DEDENT>return self._send_success_response(directory, start_response)<EOL>
Sends HTTP response containing the API directory.

        This calls start_response and returns the response body.

        Args:
          request: An ApiRequest, the transformed request sent to the Discovery API.
          start_response: A function with semantics defined in PEP-333.

        Returns:
          A string containing the response body.