@Override
    public int compareTo(DateTimeStamp dateTimeStamp) {
        return  comparator.compare(this,dateTimeStamp);
    }
@Test
    void compareToTransitivity() {
        DateTimeStamp stamp1 = new DateTimeStamp("2021-09-01T11:12:13.111-0100", 100);
        DateTimeStamp stamp2 = new DateTimeStamp((String)null, 200);
        DateTimeStamp stamp3 = new DateTimeStamp("2021-08-31T11:12:13.111-0100", 300);
        assertTrue(stamp1.compareTo(stamp2) < 0);
        assertTrue(stamp2.compareTo(stamp3) < 0);
        assertTrue(stamp1.compareTo(stamp3) < 0);
    }