public boolean isValid() {
        return !Double.isNaN(lat) && !Double.isNaN(lon);
    }
@Test
    public void testIsValid() {
        GHPoint instance = new GHPoint();
        assertFalse(instance.isValid());
        instance.lat = 1;
        assertFalse(instance.isValid());
        instance.lon = 1;
        assertTrue(instance.isValid());
    }