Memoized Method descriptor

memoized.py

from functools import partial


class MemoizedMethod:
    def __init__(self, func):
        self.func = func

    def __get__(self, obj, objtype=None):
        if obj is None:
            return self.func
        return partial(self, obj)

    def __call__(self, obj, *args, **kw):
        try:
            cache = obj.__memo_cache
        except AttributeError:
            cache = obj.__memo_cache = {}

        key = (self.func, args, frozenset(kw.items()))
        try:
            res = cache[key]
        except KeyError:
            res = cache[key] = self.func(obj, *args, **kw)

        return res


memoized_method = MemoizedMethod