code: def _metadata_endpoint(self, context):
          
          satosa_logging(logger, logging.DEBUG, "Sending metadata response", context.state)
  
          metadata_string = create_metadata_string(None, self.sp.config, 4, None, None, None, None,
                                                   None).decode("utf-8")
          return Response(metadata_string, content="text/xml")
docs: Endpoint for retrieving the backend metadata
          :type context: satosa.context.Context
          :rtype: satosa.response.Response
  
          :param context: The current context
          :return: response with metadata