@Override
    public ValueSet union(ValueSet other)
    {
        AllOrNoneValueSet otherValueSet = checkCompatibility(other);
        return new AllOrNoneValueSet(type, all || otherValueSet.all);
    }
@Test
    public void testUnion()
    {
        AllOrNoneValueSet all = AllOrNoneValueSet.all(HYPER_LOG_LOG);
        AllOrNoneValueSet none = AllOrNoneValueSet.none(HYPER_LOG_LOG);

        assertEquals(all.union(all), all);
        assertEquals(all.union(none), all);
        assertEquals(none.union(all), all);
        assertEquals(none.union(none), none);
    }