* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-class BaseList extends BaseFrameworkSystem implements IteratorAggregate, Countable {
+abstract class BaseList extends BaseFrameworkSystem implements IteratorAggregate, Countable {
// Exception constants
const EXCEPTION_GROUP_ALREADY_ADDED = 0xf20;
const EXCEPTION_GROUP_NOT_FOUND = 0xf21;