import functools, inspect


def proper_cache(*lru_args, **lru_kwargs):
    def deco(func):
        signature = inspect.signature(func)

        # if the function has no default parameters, return a normal lru_cache
        if all(p.default is inspect.Parameter.empty for p in signature.parameters.values()):
            return functools.lru_cache(*lru_args, **lru_kwargs)(func)

        # apply an lru_cache on the original function
        func = functools.lru_cache(*lru_args, **lru_kwargs)(func)

        # return a function that expands all default arguments
        @functools.wraps(func)
        def wrapper_func(*args, **kwargs):
            bound_args = signature.bind(*args, **kwargs)
            bound_args.apply_defaults()
            return func(*bound_args.args, **bound_args.kwargs)

        wrapper_func.cache_info = func.cache_info
        wrapper_func.cache_clear = func.cache_clear

        return wrapper_func

    return deco



@proper_cache()
def func(arg=1):
    return arg

func()
func(1)

print(func.cache_info()) # CacheInfo(hits=1, misses=1, maxsize=128, currsize=2)