def edges(self, order=None):
        """Return all the edges

        Parameters
        ----------
        order : string
            The order of the returned edges. Currently support:

            - 'srcdst' : sorted by their src and dst ids.
            - 'eid'    : sorted by edge Ids.
            - None     : the arbitrary order.

        Returns
        -------
        utils.Index
            The src nodes.
        utils.Index
            The dst nodes.
        utils.Index
            The edge ids.
        """
        if order is None:
            order = ""
        edge_array = _CAPI_DGLGraphEdges(self, order)
        src = edge_array(0)
        dst = edge_array(1)
        eid = edge_array(2)
        src = utils.toindex(src)
        dst = utils.toindex(dst)
        eid = utils.toindex(eid)
        return src, dst, eid
Return all the edges

        Parameters
        ----------
        order : string
            The order of the returned edges. Currently support:

            - 'srcdst' : sorted by their src and dst ids.
            - 'eid'    : sorted by edge Ids.
            - None     : the arbitrary order.

        Returns
        -------
        utils.Index
            The src nodes.
        utils.Index
            The dst nodes.
        utils.Index
            The edge ids.
        
python/dgl/graph_index.py