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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_subgraph_by_induction(graph, nodes: Iterable[BaseEntity]):
 """Induce a sub-graph over the given nodes or return None if none of the nodes are in the given graph. :param pybel.BELGraph graph: A BEL graph :param nodes: A list of BEL nodes in the graph :rtype: Optional[pybel.BELGraph] """

    nodes = tuple(nodes)

    if all(node not in graph for node in nodes):
        return

    return subgraph(graph, nodes)