code: public static MutableRoaringBitmap naive_xor(@SuppressWarnings("rawtypes") Iterator bitmaps) {
      MutableRoaringBitmap answer = new MutableRoaringBitmap();
      while (bitmaps.hasNext()) {
        answer.xor((ImmutableRoaringBitmap) bitmaps.next());
      }
      return answer;
    }
docs: Compute overall XOR between bitmaps two-by-two.
  
  This function runs in linear time with respect to the number of bitmaps.
  
  @param bitmaps input bitmaps (ImmutableRoaringBitmap or MutableRoaringBitmap)
  @return aggregated bitmap