说明：  尽管Python事实上并不是一门纯函数式编程语言，但它本身是一门多范型语言，并给了你足够的自由利用函数式编程的便利。函数式风格有着各种理论与实际上的好处
(Despite the fact that Python is not a purely functional programming language, but it itself is more than one-paradigm language, and gives you enough freedom to facilitate the use of functional programming. Functional style with a variety of theoretical and practical benefits)