class RemovableKeySet extends KeySet {

    @SuppressWarnings("unchecked")
    @Override
    public boolean removeAll(Collection<?> c) {
        Collection<String> realCollection = (Collection<String>) c;
        boolean retValue = false;
        for (String entry : realCollection) {
            retValue |= remove(entry);
        }
        return retValue;
    }

    public  RemovableKeySet(HasRemovableKeys<?> request);

}