从装饰器访问拥有装饰方法的类

def my_decorator(func):
    def wrapper():
        print("Something is happening before the function is called.")
        func()
        print("Something is happening after the function is called.")
    return wrapper

def say_hello():
    print("Hello!")

say_hello = my_decorator(say_hello)

say_hello()

class MyClass:
    def my_method(self):
        print("Hello from MyClass!")

def my_decorator(cls):
    class Wrapper:
        def __init__(self):
            self.instance = cls()

        def my_method(self):
            print("Something is happening before the method is called.")
            self.instance.my_method()
            print("Something is happening after the method is called.")

    return Wrapper

MyClass = my_decorator(MyClass)

obj = MyClass()
obj.my_method()