动物园：https://python.tutorial.hogwarts.ceshiren.com/python_programming/v2/L2/homework/【练习】员工薪资/
员工薪资:
https://python.tutorial.hogwarts.ceshiren.com/python_programming/v2/L2/homework/【练习】员工薪资/
英雄游戏（到封装、继承、多态）：
https://python.tutorial.hogwarts.ceshiren.com/python_programming/v2/L2/homework/【练习】英雄游戏/
图书管理系统：https://python.tutorial.hogwarts.ceshiren.com/python_programming/v2/L2/homework/【练习】图书管理系统/