1 def sheep(f):
 2     def she():
 3         print("I'm a sheep")
 4         return f()
 5     return she
 6 
 7 @sheep
 8 def wolf():
 9     print("I'm a wolf")
10 
11 if __name__ == "__main__":
12     wolf()

I'm a sheep
I'm a wolf

wolf = sheep(wolf)
wolf()

 1 def change(a):
 2     def sheep(f):
 3         def she():
 4             print("I'm a sheep")
 5             f()
 6             print("you're not ,you're {} sheep".format(a))
 7         return she
 8     return sheep
 9 
10 @change("fake")
11 def wolf():
12     print("I'm a wolf")
13 
14 if __name__ == "__main__":
15     wolf()

I'm a sheep
I'm a wolf
you're not ,you're fake sheep

wolf = change("fake")(wolf)
wolf()

 1 import functools
 2 
 3 def change(a):
 4     def sheep(f):
 5         @functools.wraps(f)
 6         def she():
 7             print("I'm a sheep")
 8             f()
 9             print("you're not ,you're {} sheep".format(a))
10         return she
11     return sheep
12 
13 def wolf():
14     print("I'm a wolf")
15 
16 if __name__ == "__main__":
17     wolf = change("fake")(wolf)
18     wolf()