code: public PreUpdate<MappedSuperclass<T>> getOrCreatePreUpdate()
     {
        Node node = childNode.getOrCreate("pre-update");
        PreUpdate<MappedSuperclass<T>> preUpdate = new PreUpdateImpl<MappedSuperclass<T>>(this, "pre-update", childNode, node);
        return preUpdate;
     }
docs: If not already created, a new <code>pre-update</code> element with the given value will be created.
  Otherwise, the existing <code>pre-update</code> element will be returned.
  @return  a new or existing instance of <code>PreUpdate<MappedSuperclass<T>></code>