code: func (s *sequence) getCopy() *sequence {
  	n := &sequence{block: s.block, count: s.count}
  	pn := n
  	ps := s.next
  	for ps != nil {
  		pn.next = &sequence{block: ps.block, count: ps.count}
  		pn = pn.next
  		ps = ps.next
  	}
  	return n
  }
docs: // GetCopy returns a copy of the linked list rooted at this node