def test_is_empty(self):
"""Test is empty method."""
d = Dequeue()
self.assertTrue(d.is_empty())
d.add_front(1)
self.assertFalse(d.is_empty())
def test_is_empty(self):
d = Dequeue()
self.assertEqual(d.is_empty(), True)
d.add_front("apple")
self.assertEqual(d.is_empty(), False)