docs: public static MutableRoaringBitmap naive_and(MutableRoaringBitmap... bitmaps) {
      if (bitmaps.length == 0) {
        return new MutableRoaringBitmap();
      }
      MutableRoaringBitmap answer = bitmaps[0].clone();
      for (int k = 1; k < bitmaps.length; ++k) {
        answer.and(bitmaps[k]);
      }
      return answer;
    }