public function isRequired()
    {
        $isRequired = $this->attribs['required'];
        if (\is_string($isRequired)) {
            $replaced = \preg_replace('/{{(.*?)}}/', '$this->form->getField("$1")->val()', $isRequired);
            $evalString = '$isRequired = (bool) '.$replaced.';';
            eval($evalString);
        }
        return $isRequired;
    }