public boolean hasDateStamp() {
        return ! (getDateTime() == null || EPOC.equals(getDateTime()));
    }
@Test
    void hasDateStamp() {
        DateTimeStamp dateTimeStamp = new DateTimeStamp(.586);
        assertFalse(dateTimeStamp.hasDateStamp());

        dateTimeStamp = new DateTimeStamp("2018-04-04T09:10:00.586-0100");
        assertTrue(dateTimeStamp.hasDateStamp());

        dateTimeStamp = new DateTimeStamp("2018-04-04T09:10:00.586-0100", 0.18);
        assertTrue(dateTimeStamp.hasDateStamp());
    }