code: public static function range($gte, $lte, $message = null)
      {
          if ($message === null) {
              $message = "Value must be between $gte and $lte";
          }
  
          return new ResultsIn\OutcomeRule(new Psi\IsInRange($gte, $lte), $message);
      }
docs: @param float  $gte
  @param float  $lte
  @param string $message
  
  @return ResultsIn\OutcomeRule