python LRU cache instance method return value

lru_cache.py

from functools import lru_cache, wraps


class cached_method:
    """Decorotor for class methods.
    Using pythons non data descriptor protocol, creates a new `functools.lru_cache` funcion wrapper
    on first access of a instances method to cache the methods return value.
    """
    def __new__(cls, func=None, **lru_kwargs):
        if func is None:
            def decorator(func):
                return cls(func=func, **lru_kwargs)
            return decorator
        return super().__new__(cls)

    def __init__(self, func=None, **lru_kwargs):
        self.func = func
        self.name = func.__name__
        self.lru_kwargs = lru_kwargs

    def __get__(self, instance, owner):
        if not instance:
            return self

        @wraps(self.func)
        def decorated_func(*args, **kwargs):
            return self.func(instance, *args, **kwargs)

        lru_cache_warpper = lru_cache(**self.lru_kwargs)(decorated_func)
        instance.__dict__[self.name] = lru_cache_warpper
        return lru_cache_warpper