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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_graph(self, run_key, device_name, debug=False):
 """Get the runtime GraphDef proto associated with a run key and a device. Args: run_key: A Session.run kay. device_name: Name of the device in question. debug: Whether the debugger-decoratedgraph is to be retrieved. Returns: A `GraphDef` proto. """

    return self.get_graphs(run_key, debug=debug).get(device_name, None)