class ScopedSet implements ScopeSubscriber, Set<E> {

    public boolean removeAll(final Collection<?> c) {
        boolean changed = false;
        for (Object o : c) {
            if (remove(o) && !changed) {
                changed = true;
            }
        }

        return changed;
    }

    public  ScopedSet(final ScopeObserver scopeObserver);

}