def test_equals_2(self): self.assertEqual(add_check_digit('12388878'), '123888782')
def test_equals_4(self): self.assertEqual(add_check_digit('9735597355'), '97355973550')
def test_equals(self): self.assertEqual(add_check_digit('111111111'), '1111111118')
def test_equals_3(self): self.assertEqual(add_check_digit('036532'), '0365327')