presto-spi/src/main/java/io/prestosql/spi/type/RealType.java/RealType/getRange
class RealType:    @Override
    public Optional<Range> getRange()
    {
        // The range for real is undefined because NaN is a special value that
        // is *not* in any reasonable definition of a range for this type.
        return Optional.empty();
    }