Class Decorator

class count_calls(object):
    counterdict = {}

    def __init__(self, fn):
        self.fn = fn
        self.func_name = self.fn.__name__
        if not self.func_name in self.counterdict:
            self.counterdict[self.func_name] = 0

    def __call__(self, *args, **kwargs):
        self.counterdict[self.func_name] += 1
        return self.fn(*args, **kwargs)

    def counter(self):
        return self.counterdict[self.func_name]

    @classmethod
    def counters(cls):
        return cls.counterdict

    @classmethod
    def reset_counters(cls):
        cls.counterdict = {}

@count_calls
def adding(*args):
    return sum(args)

>>> adding(1, 2)
3
>>> adding(3, 4)
7
>>> adding(5, 6)
11
>>> adding.counter()
3
>>> adding.counters()
{'adding': 3}
>>> adding.reset_counters()
>>> adding.counters()
{}