@lru_cache can be used elegantly to create a cache with a time-to-live, if a time parameter is used to invalidate previous responses:

from functools import lru_cache
import time
def my_expensive_function(a, b, ttl_hash=None):
    del ttl_hash  # to emphasize we don't use it and to shut pylint up
    return a + b
def get_ttl_hash(seconds=3600):
    """Return the same value within `seconds` time period"""
    return round(time.time() / seconds)
# somewhere in your code...
res = my_expensive_function(2, 2, ttl_hash=get_ttl_hash())
# cache will be updated once in an hour


A more elegant version that does not require external parameters (source):

from functools import lru_cache, wraps
from datetime import datetime, timedelta
def timed_lru_cache(seconds: int, maxsize: int = 128):
    def wrapper_cache(func):
        func = lru_cache(maxsize=maxsize)(func)
        func.lifetime = timedelta(seconds=seconds)
        func.expiration = datetime.utcnow() + func.lifetime
        def wrapped_func(*args, **kwargs):
            if datetime.utcnow() >= func.expiration:
                func.expiration = datetime.utcnow() + func.lifetime
            return func(*args, **kwargs)
        return wrapped_func
    return wrapper_cache