docs: public static MutableRoaringBitmap naive_xor(@SuppressWarnings("rawtypes") Iterator bitmaps) {
      MutableRoaringBitmap answer = new MutableRoaringBitmap();
      while (bitmaps.hasNext()) {
        answer.xor((ImmutableRoaringBitmap) bitmaps.next());
      }
      return answer;
    }