def _get_e_repr(self, etid, edges):
        """Internal API to get edge features.

        Parameters
        ----------
        etid : int
            Edge type id.
        edges : edges
            Edges can be a pair of endpoint nodes (u, v), or a
            tensor of edge ids. The default value is all the edges.

        Returns
        -------
        dict
            Representation dict
        """
        # parse argument
        if is_all(edges):
            return self._edge_frames[etid]
        else:
            eid = utils.parse_edges_arg_to_eid(self, edges, etid, "edges")
            return self._edge_frames[etid].subframe(eid)
Internal API to get edge features.

        Parameters
        ----------
        etid : int
            Edge type id.
        edges : edges
            Edges can be a pair of endpoint nodes (u, v), or a
            tensor of edge ids. The default value is all the edges.

        Returns
        -------
        dict
            Representation dict
        
python/dgl/heterograph.py