@Override
 public <T extends Entity<?, ?>> Iterator<T> getTransitiveClosureOver(
     CanonicalPath startingPoint,
     Relationships.Direction direction,
     Class<T> clazz,
     String... relationshipNames) {
   return backend.getTransitiveClosureOver(startingPoint, direction, clazz, relationshipNames);
 }
 @Override
 public Iterator<E> getTransitiveClosureOver(
     E startingPoint, Relationships.Direction direction, String... relationshipNames) {
   return backend.getTransitiveClosureOver(startingPoint, direction, relationshipNames);
 }