def runTest(self):
     k = MyGraph([[0, 1, 0], [0, 2, 1], [0, 3, 2], [1, 2, 3], [1, 3, 4],
                  [2, 3, 5]])
     self.assertEqual(k.find_divalent_vertex(), None)
     l = k.edge_deletion(0)
     self.assertItemsEqual(l.find_divalent_vertex()[1:], (2, 3))
 def runTest(self):
     k = MyGraph(dart_partitions=[[[1, 2]], [[1, 2]]])
     res = k.find_divalent_vertex()
     self.assertEqual(res, (0, 0, 0))
 def runTest(self):
     k = MyGraph(**self.data["3-gon"])
     self.assertItemsEqual(k.find_divalent_vertex(), (0, 1, 2))
     self.assertEqual(k.find_divalent_vertex()[0], 0)