yii\validators\RangeValidator::validateValue PHP Method

    protected function validateValue($value)
    {
        $in = false;
        if ($this->allowArray && ($value instanceof \Traversable || is_array($value)) && ArrayHelper::isSubset($value, $this->range, $this->strict)) {
            $in = true;
        }
        if (!$in && ArrayHelper::isIn($value, $this->range, $this->strict)) {
            $in = true;
        }
        return $this->not !== $in ? null : [$this->message, []];
    }