Eris\Generator\ArithmeticProgression::discrete PHP 메소드

    public static function discrete($lowerLimit)
    {
        return new self($lowerLimit);
    }

 public function __construct($lowerLimit, $upperLimit)
 {
     $this->lowerLimit = $lowerLimit;
     $this->upperLimit = $upperLimit;
     $this->shrinkingProgression = ArithmeticProgression::discrete($this->lowerLimit);
 }