def test_edges_between_different_nodes_should_be_a_single_arrow(self):
        gr = graph()
        gr.add_node(0)
        gr.add_edge((0,0), label="label", attrs=[('key','value')])
        assert gr.edges() in (0,0)
        assert len(gr.edges()) == 1
        assert gr.neighbors(0) == [0]
        assert (0,0) in gr.edge_properties.keys()
        assert (0,0) in gr.edge_attr.keys()
        assert len(gr.edge_attr[(0,0)]) == 1

    
    # Invert graph
dataset/ETHPy150Open pmatiello/python-graph/tests/unittests-graph.py/test_graph.test_edges_between_different_nodes_should_be_a_single_arrow/swapped operands of `in`