member

member is a python library that introduces instance-stored memoized functions

Example: Fibonacci numbers

from member import member


class FibonacciSeries:
    def __init__(self, starters=(0, 1)):
        self.n = len(starters)
        for i, v in enumerate(starters):
            self.__call__[i] = v

    @member
    def __call__(self, index):
        return sum(self(index - i) for i in range(1, self.n + 1))


f = FibonacciSeries()
assert f(10) == 55

What's wrong with lru_cache?

functools.lru_cache is a very powerful tool to memoize functions, and it can even work on class methods! Its weak point is that it stores the instance (self) as part of the the cache key, and the cache is stored in the class namespace. Meaning that unless the user calls lru_cache.cache_clear(), then any instance of the class that calls the memoized methods will never be deleted.