Convenience function to access ``TFNode.DataFeed`` directly from this object instance.

def get_data_feed(self, train_mode=True, qname_in='input', qname_out='output', input_mapping=None):
    """Convenience function to access ``TFNode.DataFeed`` directly from this object instance."""
    return TFNode.DataFeed(self.mgr, train_mode, qname_in, qname_out, input_mapping)