- Music * m = dynamic_cast<Music_wrapper const*> (get_music ())-> element();
- child_iter_ = unsmob_iterator (get_iterator (m));
+ Music *my_music = get_music ();
+ Music *child = unsmob_music (my_music->get_property ("element"));
+ child_iter_ = (child)
+ ? unsmob_iterator (get_iterator (child))
+ : 0;