def make_bold(fn):  
    def wrapped():  
        return "<b>" + fn() + "</b>"  
    return wrapped  
  
def make_italic(fn):  
    def wrapped():  
        return "<i>" + fn() + "</i>"  
    return wrapped  
  
def make_underline(fn):  
    def wrapped():  
        return "<u>" + fn() + "</u>"  
    return wrapped  
@make_bold  
@make_italic  
@make_underline  
def hello():  
    return "hello world"  
print(hello()) ## returns "<b><i><u>hello world</u></i></b>" 