@Test
  public void test1() {

    assertTrue(validatorC2.isValid("2394871426"));
    assertTrue(validatorC2.isValid("4218461950"));
    assertTrue(validatorC2.isValid("7352569148"));

    assertTrue(validatorC2.isValid("5127485166"));
    assertTrue(validatorC2.isValid("8738142564"));
  }
  @Test
  public void test2() {

    assertFalse(validatorC2.isValid("0328705282"));
    assertFalse(validatorC2.isValid("9024675131"));
  }