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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 update_node_helper(source: nx.Graph, target: nx.Graph) -> None: """Update the nodes' data dictionaries in the target graph from the source graph. :param source: The universe of all knowledge :param target: The target BEL graph """

    for node in target:
        if node in source:
            target.nodes[node].update(source.nodes[node])