code: func (s *SeriesIDSet) AndNot(other *SeriesIDSet) *SeriesIDSet {
  	s.RLock()
  	defer s.RUnlock()
  	other.RLock()
  	defer other.RUnlock()
  
  	return &SeriesIDSet{bitmap: roaring.AndNot(s.bitmap, other.bitmap)}
  }
docs: // AndNot returns a new SeriesIDSet containing elements that were present in s,
  // but not present in other.