code: def rollback(self):
          
          if self._status != self._IN_PROGRESS:
              raise ValueError("Batch must be in progress to rollback()")
  
          self._status = self._ABORTED
docs: Rolls back the current batch.
  
          Marks the batch as aborted (can't be used again).
  
          Overridden by :class:`google.cloud.datastore.transaction.Transaction`.
  
          :raises: :class:`~exceptions.ValueError` if the batch is not
                   in progress.