protected function set_new_path(competency $parent = null) {
        $path = '/0/';
        if ($this->get('parentid')) {
            $parent = $parent !== null ? $parent : $this->get_parent();
            $path = $parent->get('path') . $this->get('parentid') . '/';
        }
        $this->raw_set('path', $path);
    }