code: func (b *OpenBitSet) remove(other *OpenBitSet) {
  	idx := b.wlen
  	if other.wlen < idx {
  		idx = other.wlen
  	}
  	thisArr := b.bits
  	otherArr := other.bits
  	for pos := idx - 1; pos >= 0; pos-- {
  		thisArr[pos] &= ^otherArr[pos]
  	}
  }
docs: //L760