def test_10(self):
""" test peek() for return value """
d = Dequeue()
n1 = Node(1)
n2 = Node(2)
d.append(n1)
d.append(n2)
self.assertEqual(d.peek(), 2)
def test_11(self):
""" test peek() for empty dequeue """
d = Dequeue()
self.assertEqual(d.peek(), None)