code: public PartialResponseErrorType<PartialResponseType<T>> getOrCreateError()
     {
        Node node = childNode.getOrCreate("error");
        PartialResponseErrorType<PartialResponseType<T>> error = new PartialResponseErrorTypeImpl<PartialResponseType<T>>(this, "error", childNode, node);
        return error;
     }
docs: If not already created, a new <code>error</code> element with the given value will be created.
  Otherwise, the existing <code>error</code> element will be returned.
  @return  a new or existing instance of <code>PartialResponseErrorType<PartialResponseType<T>></code>