public function set($value) {
        $finalgrade = false;
        $trimmed = trim($value);
        if (empty($trimmed)) {
            $feedback = null;
        } else {
            $feedback = $value;
        }

        $this->grade->grade_item->update_final_grade(
            $this->grade->userid, $finalgrade, 'singleview',
            $feedback, FORMAT_MOODLE
        );
    }