function write_setting($data) {
        global $CFG;

        $previous = $this->get_setting();
        $result = parent::write_setting($data);

        // If saved and the value has changed.
        if (empty($result) && $previous != $data) {
            require_once($CFG->libdir . '/gradelib.php');
            grade_force_site_regrading();
        }

        return $result;
    }