@Override
 protected XIterator<K> createBaseView(XOrderedKeySetView<K> baseKeySet, ViewInfo viewInfo) {
   if (viewInfo instanceof OrderedSetViewInfos.DescendingIterator) {
     return baseKeySet.descendingIterator();
   }
   throw new IllegalArgumentException(LAZY_COMMON_RESOURCE.get().illegalViewInfo());
 }
 @Override
 protected XOrderedKeySetView<K> createBaseView(
     XOrderedKeySetView<K> parentBase, ViewInfo viewInfo) {
   if (viewInfo instanceof OrderedSetViewInfos.DescendingSet) {
     return parentBase.descendingSet();
   }
   throw new IllegalArgumentException(LAZY_COMMON_RESOURCE.get().illegalViewInfo());
 }