src/main/java/org/organicdesign/fp/collections/RangeOfInt.java
public static RangeOfInt of(Number s, Number e) {
        if ((s == null) || (e == null)) {
            throw new IllegalArgumentException("Nulls not allowed");
        }
        if (e.longValue() < s.longValue()) {
            throw new IllegalArgumentException("end of range must be >= start of range");
        }
        return new RangeOfInt(s.intValue(), e.intValue());
    }
public static RangeOfInt of(Number s, Number e) {
        if ((s == null) || (e == null)) {
            throw new IllegalArgumentException("Nulls not allowed");
        }
        if (e.longValue() < s.longValue()) {
            throw new IllegalArgumentException("end of range must be >= start of range");
        }
        return new RangeOfInt(s.intValue(), e.intValue());
    }
}