code: func (b *Bitmap) Intersect(other *Bitmap) *Bitmap {
  	output := NewBitmap()
  	iiter, _ := b.Containers.Iterator(0)
  	jiter, _ := other.Containers.Iterator(0)
  	i, j := iiter.Next(), jiter.Next()
  	ki, ci := iiter.Value()
  	kj, cj := jiter.Value()
  	for i && j {
  		if ki < kj {
  			i = iiter.Next()
  			ki, ci = iiter.Value()
  		} else if ki > kj {
  			j = jiter.Next()
  			kj, cj = jiter.Value()
  		} else { // ki == kj
  			output.Containers.Put(ki, intersect(ci, cj))
  			i, j = iiter.Next(), jiter.Next()
  			ki, ci = iiter.Value()
  			kj, cj = jiter.Value()
  		}
  	}
  	return output
  }
docs: // Intersect returns the intersection of b and other.