code: def finish(self):
          
          headers, body = self._prepare_batch_request()
  
          url = "%s/batch/storage/v1" % self.API_BASE_URL
  
          # Use the private ``_base_connection`` rather than the property
          # ``_connection``, since the property may be this
          # current batch.
          response = self._client._base_connection._make_request(
              "POST", url, data=body, headers=headers
          )
          responses = list(_unpack_batch_response(response))
          self._finish_futures(responses)
          return responses
docs: Submit a single `multipart/mixed` request with deferred requests.
  
          :rtype: list of tuples
          :returns: one ``(headers, payload)`` tuple per deferred request.