了解python的装饰器特性

装饰器相当于一个装饰，不修改函数原本内容，只是增添内容

def my_decorator(func):
    def warpper():
        print("有函数要执行了")
        func()
        print("有函数执行完毕")

    return warpper

@my_decorator
def say_hello():
    print("hello")


say_hello()

相当于

def my_decorator(func):
    def warpper():
        print("有函数要执行了")
        func()
        print("有函数执行完毕")

    return warpper


def say_hello():
    print("hello")


my_decorator(say_hello)()