Get the neighborhood graph of a node.

        :param str node_name: Node whose neighborhood graph is requested.
        :return Graph: Neighborhood graph

def get_neighborhood_network(self, node_name: str, order: int = 1) -> Graph:
        """Get the neighborhood graph of a node.

        :param str node_name: Node whose neighborhood graph is requested.
        :return Graph: Neighborhood graph
        """
        logger.info("In get_neighborhood_graph()")
        neighbors = list(self.get_neighbor_names(node_name, order))
        neighbor_network = self.graph.copy()
        neighbor_network.delete_vertices(self.graph.vs.select(name_notin=neighbors))
        return neighbor_network