参考资料
[1] 12步理解Python装饰器,https://dzone.com/articles/understanding-python (网上也有中文翻译版,建议阅读英文原版)
[2] Python装饰器简介,http://www.artima.com/weblogs/viewpost.jsp?thread=240808
[3] Python面试题,http://keyanwu.gitcafe.io/pythonmian-shi-ti.html
[4] Python装饰器详解,https://segmentfault.com/a/1190000000632572
[5] 深入Python装饰器,https://github.com/Vamei/Python-Tutorial-Vamei/blob/master/content/%E6%B7%B1%E5%85%A505%20%E8%A3%85%E9%A5%B0%E5%99%A8.md