code: def commit(self):
          
          if self._status != self._IN_PROGRESS:
              raise ValueError("Batch must be in progress to commit()")
  
          try:
              self._commit()
          finally:
              self._status = self._FINISHED
docs: Commits the batch.
  
          This is called automatically upon exiting a with statement,
          however it can be called explicitly if you don't want to use a
          context manager.
  
          :raises: :class:`~exceptions.ValueError` if the batch is not
                   in progress.