+ public Iterable<HierarchyUnit> getDirectHierachyUnits(boolean functionalOnly) {
+// 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);