Resources about refactoring
The Simple Ways to Refactor Terrible Code
https://towardsdatascience.com/the-simple-ways-to-refactor-terrible-code-983f563964fc
代码重构新手教程:如何将烂代码变成好代码?
https://www.infoq.cn/article/vckes7xg4ez21wxdq8rd
Python代码重构指南
https://time.geekbang.org/course/intro/100059301
Refactoring in Python LiveLessons: Improving Your Code Video Training
https://github.com/BillyGarnet/Refactoring-in-Python-Examples