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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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)