'Multidigraphs are acceptable.'

def test_multidigraph(self):

    G = nx.MultiDiGraph()
    G.add_weighted_edges_from([(1, 2, 1), (2, 3, 2)], weight='capacity')
    (flowCost, H) = nx.network_simplex(G)
    assert_equal(flowCost, 0)
    assert_equal(H, {1: {2: {0: 0}}, 2: {3: {0: 0}}, 3: {}})
    (flowCost, H) = nx.capacity_scaling(G)
    assert_equal(flowCost, 0)
    assert_equal(H, {1: {2: {0: 0}}, 2: {3: {0: 0}}, 3: {}})
