from functools import wraps

class Formatter(object):
    def cap(self):
        def cap_decorator(func):
            @wraps(func)
            def func_wrapper(value):
                return func(value).upper()
            return func_wrapper
        return cap_decorator

formatter = Formatter()

class Person(object):

    def __init__(self, name):
        self.name = name

    @formatter.cap()
    def sayHi(self):
        return self.name

bob = Person('Bob')
print bob.sayHi()