public static function view_grading_table($assignid) {

        $params = self::validate_parameters(self::view_grading_table_parameters(),
                                            array(
                                                'assignid' => $assignid
                                            ));
        $warnings = array();

        list($assign, $course, $cm, $context) = self::validate_assign($params['assignid']);

        $assign->require_view_grades();
        \mod_assign\event\grading_table_viewed::create_from_assign($assign)->trigger();

        $result = array();
        $result['status'] = true;
        $result['warnings'] = $warnings;
        return $result;
    }