class Thresholds

final class Thresholds {
    private readonly int $lowUpperBound;
    private readonly int $highLowerBound;
    public static function default() : self {
        return new self(50, 90);
    }
    
    /**
     * @throws InvalidArgumentException
     */
    public static function from(int $lowUpperBound, int $highLowerBound) : self {
        if ($lowUpperBound > $highLowerBound) {
            throw new InvalidArgumentException('$lowUpperBound must not be larger than $highLowerBound');
        }
        return new self($lowUpperBound, $highLowerBound);
    }
    private function __construct(int $lowUpperBound, int $highLowerBound) {
        $this->lowUpperBound = $lowUpperBound;
        $this->highLowerBound = $highLowerBound;
    }
    public function lowUpperBound() : int {
        return $this->lowUpperBound;
    }
    public function highLowerBound() : int {
        return $this->highLowerBound;
    }

}