* This method is only for tests.
* @param ds WriteableDatasource that can be cast to CNDatasource.
* @throws Exception in case of ObjectManagementError.
*/
public static void importObjectTypes(WriteableDatasource ds, InputStream stream) throws Exception {
CNDatasource cnds = (CNDatasource) ds;
try {
ObjectManagementManager.importTypes((CNDatasource) ds, stream);
} catch (ObjectManagementException e) {
throw new Exception(e);
}