code: func (iter *iterator) Next() bool {
  	if iter.first {
  		iter.first = false
  		return iter.n != nil
  	}
  
  	if iter.n == nil {
  		return false
  	}
  
  	iter.n = iter.n.forward[0]
  	return iter.n != nil
  }
docs: // Next returns a bool indicating if there are any further values
  // in this iterator.