並前往https://github.com/dokelung/Python-QA/blob/master/questions/sort/sorted%E5%87%BD%E6%95%B8%E4%B8%ADkey%E5%8F%83%E6%95%B8%E7%9A%84%E4%BD%9C%E7%94%A8%E5%8E%9F%E7%90%86.md
