写了很久的Python，我对这两个概念一致都是很陌生的感觉。你可能早就放弃了Python这个特性，但是我建议还是要深入了解它。
After writing Python for a long time, I still feel I am unfamiliar with these concepts. You may have abandoned this feature, but I suggest that you still need to understand it.
本工程参考了dabeaz相关示例代码，大家可以直接阅读
This project refers to sample code of dabeaz. Everyone can read it.