code: def save_response(self, service, operation, response_data,
                        http_response=200):
          
          LOG.debug('save_response: %s.%s', service, operation)
          filepath = self.get_new_file_path(service, operation)
          LOG.debug('save_response: path=%s', filepath)
          data = {'status_code': http_response,
                  'data': response_data}
          with open(filepath, Format.write_mode(self.record_format)) as fp:
              self._serializer(data, fp)
docs: Store a response to the data directory.  The ``operation``
          should be the name of the operation in the service API (e.g.
          DescribeInstances), the ``response_data`` should a value you want
          to return from a placebo call and the ``http_response`` should be
          the HTTP status code returned from the service.  You can add
          multiple responses for a given operation and they will be
          returned in order.