def test_equal_1(self): self.assertEqual(list(sort([])), [])
def test_equal_2(self): self.assertEqual(list(sort(['z', 'x', 'w', 'y'])), ['w', 'x', 'y', 'z'])
def test_equal_3(self): self.assertEqual(list(sort(['b', 'ba', 'ab', 'bb', 'c'])), ['ab', 'b', 'ba', 'bb', 'c'])