int depthHelper(int depth) { if (getParentAlbum() != null && getParentAlbum() != this) {
int depthHelper(int depth) throws IllegalArgumentException { if (getParentAlbum() == this || depth > 20) { throw new IllegalArgumentException("Circular containment hierarchy. Gallery corrupted!"); }  if (getParentAlbum() != null) {
	int depthHelper(int depth) {		if (getParentAlbum() != null && getParentAlbum() != this) {			return getParentAlbum().depthHelper(depth + 1);		} else {			return depth;		}	}