@Override
 public void iterate(@NotNull RefVisitor visitor) {
   for (RefElement refElement : getSortedElements()) {
     refElement.accept(visitor);
   }
   if (myModules != null) {
     for (RefModule refModule : myModules.values()) {
       refModule.accept(visitor);
     }
   }
   for (RefManagerExtension extension : myExtensions.values()) {
     extension.iterate(visitor);
   }
 }