def edges_iter(self, nbunch=None, data=False, keys=False):
        """Return an iterator over the edges.

        Edges are returned as tuples with optional data and keys
        in the order (node, neighbor, key, data).

        Parameters
        ----------
        nbunch : iterable container, optional (default= all nodes)
            A container of nodes.  The container will be iterated
            through once.
        data : bool, optional (default=False)
            If True, return edge attribute dict with each edge.
        keys : bool, optional (default=False)
            If True, return edge keys with each edge.

        Returns
        -------
        edge_iter : iterator
            An iterator of (u,v), (u,v,d) or (u,v,key,d) tuples of edges.

        See Also
        --------
        edges : return a list of edges

        Notes
        -----
        Nodes in nbunch that are not in the graph will be (quietly) ignored.
        For directed graphs this returns the out-edges.

        Examples
        --------
        >>> G = nx.MultiDiGraph()
        >>> G.add_path([0,1,2,3])
        >>> [e for e in G.edges_iter()]
        [(0, 1), (1, 2), (2, 3)]
        >>> list(G.edges_iter(data=True)) # default data is {} (empty dict)
        [(0, 1, {}), (1, 2, {}), (2, 3, {})]
        >>> list(G.edges_iter([0,2]))
        [(0, 1), (2, 3)]
        >>> list(G.edges_iter(0))
        [(0, 1)]

        """
        if nbunch == None:
            nodes_nbrs = self.adj.items()
        else:
            nodes_nbrs=((n,self.adj[n]) for n in self.nbunch_iter(nbunch))
        if data:
            for n,nbrs in nodes_nbrs:
                for nbr,keydict in nbrs.items():
                    for key,data in keydict.items():
                        if keys:
                            yield (n,nbr,key,data)
                        else:
                            yield (n,nbr,data)
        else:
            for n,nbrs in nodes_nbrs:
                for nbr,keydict in nbrs.items():
                    for key,data in keydict.items():
                        if keys:
                            yield (n,nbr,key)
                        else:
                            yield (n,nbr)

    # alias out_edges to edges
dataset/ETHPy150Open networkx/networkx/networkx/classes/tests/timingclasses.py/TimingMultiDiGraph.edges_iter/operator `is` -> `==`