code: public EmbeddedId<Attributes<T>> getOrCreateEmbeddedId()
     {
        Node node = childNode.getOrCreate("embedded-id");
        EmbeddedId<Attributes<T>> embeddedId = new EmbeddedIdImpl<Attributes<T>>(this, "embedded-id", childNode, node);
        return embeddedId;
     }
docs: If not already created, a new <code>embedded-id</code> element with the given value will be created.
  Otherwise, the existing <code>embedded-id</code> element will be returned.
  @return  a new or existing instance of <code>EmbeddedId<Attributes<T>></code>