presto-spi/src/main/java/io/prestosql/spi/predicate/SortedRangeSet.java/SortedRangeSet/isSingleValue
class SortedRangeSet:    @Override
    public boolean isSingleValue()
    {
        return lowIndexedRanges.size() == 1 && lowIndexedRanges.values().iterator().next().isSingleValue();
    }