def test_12(self):
""" test peekleft() for return value """
d = Dequeue()
n1 = Node(1)
n2 = Node(2)
d.append(n1)
d.append(n2)
self.assertEqual(d.peekleft(), 1)
def test_13(self):
""" test peekleft() for empty dequeue """
d = Dequeue()
self.assertEqual(d.peekleft(), None)