code: func (l *list) Length() uint {
  	curr := l
  	length := uint(0)
  	for {
  		length += 1
  		tail, _ := curr.Tail()
  		if tail.IsEmpty() {
  			return length
  		}
  		curr = tail.(*list)
  	}
  }
docs: // Length returns the number of items in the list.