@Override
    public Object getSingleValue()
    {
        if (!isSingleValue()) {
            throw new IllegalStateException("SortedRangeSet does not have just a single value");
        }
        return lowIndexedRanges.values().iterator().next().getSingleValue();
    }
@Test
    public void testGetSingleValue()
    {
        assertEquals(SortedRangeSet.of(BIGINT, 0L).getSingleValue(), 0L);
        assertThrows(IllegalStateException.class, () -> SortedRangeSet.all(BIGINT).getSingleValue());
    }