code: def commit(self):
          
          commit_response = self._client._firestore_api.commit(
              self._client._database_string,
              self._write_pbs,
              transaction=None,
              metadata=self._client._rpc_metadata,
          )
  
          self._write_pbs = []
          self.write_results = results = list(commit_response.write_results)
          self.commit_time = commit_response.commit_time
          return results
docs: Commit the changes accumulated in this batch.
  
          Returns:
              List[google.cloud.proto.firestore.v1beta1.\
                  write_pb2.WriteResult, ...]: The write results corresponding
              to the changes committed, returned in the same order as the
              changes were applied to this batch. A write result contains an
              ``update_time`` field.