Короткий приклад декоратора з параметрами

cache_decorator.py

import functools


def pop_item(di, *, first=True):
    if first:
        it = iter(di)
    else:
        it = iter(reversed(di))
    key = next(it)
    return key, di.pop(key)

def cached(param=None, *, maxsize=None):
    def _cached(func):
        data = {}
        @functools.wraps(func)
        def _cached_inner(*args):
            if args in data:
                return data[args]
            else:
                if maxsize is not None and len(data) >= maxsize:
                    pop_item(data, first=True)
                data[args] = ret = func(*args)
                return ret
        return _cached_inner
    return _cached(param) if param else _cached


#@cached
@cached(maxsize=3)
def add(x: int, y: int) -> int:
    return x + y