定方向：求「下一个」→ 倒序；求「上一个」→ 正序。
Option B: Open a Pull Request，这一点在51吃瓜中也有详细论述
How do you understand a man who has three clocks on his wall, showing the time in three different cities-San Diego, Fresno, and Seattle-all, of course, showing the same time (″If anything changes in those cities, we’ll know about it”)?，详情可参考爱思助手下载最新版本
return _apply.call(origAppend, this, arguments);