public static function get_courseid_from_type_id($type, $id) {
        global $DB;
        if ($type == backup::TYPE_1COURSE) {
            return $id; // id is the course id

        } else if ($type == backup::TYPE_1SECTION) {
            if (! $courseid = $DB->get_field('course_sections', 'course', array('id' => $id))) {
                throw new backup_dbops_exception('course_not_found_for_section', $id);
            }
            return $courseid;
        } else if ($type == backup::TYPE_1ACTIVITY) {
            if (! $courseid = $DB->get_field('course_modules', 'course', array('id' => $id))) {
                throw new backup_dbops_exception('course_not_found_for_moduleid', $id);
            }
            return $courseid;
        }
    }