'Writing keys as edge id attributes means keys become strings.
The original keys are stored as data, so read them back in
if `make_str(key) == edge_id`
This allows the adjacency to remain the same.'

def test_more_multigraph_keys(self):

    G = nx.MultiGraph()
    G.add_edges_from([('a', 'b', 2), ('a', 'b', 3)])
    (fd, fname) = tempfile.mkstemp()
    self.writer(G, fname)
    H = nx.read_graphml(fname)
    assert_true(H.is_multigraph())
    assert_edges_equal(G.edges(keys=True), H.edges(keys=True))
    assert_equal(G._adj, H._adj)
    os.close(fd)
    os.unlink(fname)
