def subgraph(self, nbunch):
        bunch = self.nbunch_iter(nbunch)
        # create new graph and copy subgraph into it
        H = self.__class__()
        # copy node and attribute dictionaries
        for n in bunch:
            H.node[n]=self.node[n]
        # namespace shortcuts for speed
        H_succ=H.succ
        H_pred=H.pred
        self_succ=self.succ
        self_pred=self.pred
        # add nodes
        for n in H:
            H_succ[n]={}
            H_pred[n]={}
        # add edges
        for u in H_succ:
            Hnbrs=H_succ[u]
            for v,edgedict in self_succ[u].items():
                if v in H_succ:
                    # add both representations of edge: u-v and v-u
                    # they share the same edgedict
                    ed=edgedict.copy()
                    Hnbrs[v]=ed
                    H_pred[v][u]=ed
        H.graph=self.graph
        return H
Return the subgraph induced on nodes in nbunch.
dataset/ETHPy150Open gkno/gkno_launcher/src/networkx/classes/multidigraph.py/MultiDiGraph.subgraph