protected function getLowerRoles(array $elements, $parentId = 0, &$return = [])
    {
        foreach ($elements as $element) {
            if ($element['parent_id'] != $parentId) {
                continue;
            }
            $children = $this->getLowerRoles($elements, $element['id'], $return);
            if ($children) {
                foreach ($children as $child) {
                    $return[] = $child['id'];
                }
            }
            $return[] = $element['id'];
        }

        return array_filter($return);
    }