decorators, python

decorators.py

def null_decorator(func):
    return func


def uppercase(func):
    def wrapper():
        original = func()
        modified = original.upper()
        return modified
    return wrapper


def strong(func):
    def wrapper():
        return '<strong>' + func() + '</strong>'
    return wrapper


def emphasis(func):
    def wrapper():
        return '<em>' + func() + '</em>'
    return wrapper


@null_decorator
def greet():
    return 'Hello!'


print(greet())
# Hello!


@uppercase
def greet():
    return 'Hello!'


print(greet())
# HELLO!


@strong
def greet():
    return 'Hello!'


print(greet())
# <strong>Hello!</strong>


@strong
@emphasis
@uppercase
def greet():
    return 'Hello!'


print(greet())
# <strong><em>HELLO!</em></strong>