class DatastoreExportOperator(BaseOperator):
    """ (...) """
    @apply_defaults
    def __init__(self,
                 bucket,
                 namespace=None,
                 datastore_conn_id='google_cloud_default',
                 (...)
                 overwrite_existing=False,
                 *args,
                 **kwargs):
        super(DatastoreExportOperator, self).__init__(*args, **kwargs)
        self.datastore_conn_id = datastore_conn_id
        (...)
        if kwargs.get('xcom_push') is not None:
            raise AirflowException("'xcom_push' was deprecated, use 'BaseOperator.do_xcom_push' instead")