class DoubleRange {

    public static DoubleRange union(DoubleRange first, DoubleRange second)
    {
        requireNonNull(first, "first is null");
        requireNonNull(second, "second is null");
        return new DoubleRange(min(first.min, second.min), max(first.max, second.max));
    }

    public  DoubleRange(double min, double max);

}