public static function get_records_select($select, $params = null, $sort = '', $fields = '*', $limitfrom = 0, $limitnum = 0) {
        global $DB;

        $records = $DB->get_records_select(static::TABLE, $select, $params, $sort, $fields, $limitfrom, $limitnum);

        // We return class instances.
        $instances = array();
        foreach ($records as $key => $record) {
            $instances[$key] = new static(0, $record);
        }

        return $instances;

    }