-// List<HierarchyUnit> res = new ArrayList<>();
-// if (functionalOnly)
-// for (HierarchyUnit hu : children) {
-// if (hu.isFunctional())
-// res.add(hu);
-// }
-// else
-// res.addAll(children);
-// return Collections.unmodifiableList(res);
- return directory.doGetDirectHierarchyUnits(dn, functionalOnly);