def test_equals(self): self.assertEqual(duplicate([2, 3, 4, 1, 3]), 3)
def test_equals_2(self): self.assertEqual(duplicate([1, 2, 3, 1, 2, 3]), 1)
def test_equals_3(self): self.assertEqual(duplicate([66, 55, 44, 33, 22, 44, 11, 11]), 44)