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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 _create_node(self, index: int, name: str, external_id: Optional[str] = None) -> IGraphNode: """ Returns a new `IGraphNode` instance with the given index and name. Arguments: index (int):
 The index of the node to create. name (str):
 The name of the node to create. external_id (Optional[str]):
 The external ID of the node. """

        return IGraphNode(graph=self._graph, index=index, name=name, external_id=external_id)