protected function addNewValues(array $selections, array $values)
    {
        if ($this->isAllowAdd()) {
            foreach ($values as $value) {
                if (!\in_array($value, $selections) && !\in_array((string) $value, $selections)) {
                    $selections[] = (string) $value;
                }
            }
        }

        return $selections;
    }