def edge_subgraph(self, induced_edges, preserve_nodes):
        """Return the induced edge subgraph.

        Parameters
        ----------
        induced_edges : list of utils.Index
            Induced edges. The length should be equal to the number of
            edge types in this heterograph.
        preserve_nodes : bool
            Indicates whether to preserve all nodes or not.
            If true, keep the nodes which have no edge connected in the subgraph;
            If false, all nodes without edge connected to it would be removed.

        Returns
        -------
        SubgraphIndex
            The subgraph index.
        """
        eids = [F.to_dgl_nd(edges) for edges in induced_edges]
        return _CAPI_DGLHeteroEdgeSubgraph(self, eids, preserve_nodes)
Return the induced edge subgraph.

        Parameters
        ----------
        induced_edges : list of utils.Index
            Induced edges. The length should be equal to the number of
            edge types in this heterograph.
        preserve_nodes : bool
            Indicates whether to preserve all nodes or not.
            If true, keep the nodes which have no edge connected in the subgraph;
            If false, all nodes without edge connected to it would be removed.

        Returns
        -------
        SubgraphIndex
            The subgraph index.
        
python/dgl/heterograph_index.py