from cachetools import TTLCache 
import time

cache = TTLCache(maxsize=10, ttl=10)

cache['city'] = 'Toronto'

print(cache['city'])

Toronto

time.sleep(5)

if('city' in cache):
    print(cache['city'])
else:
    print('Cache not found')

Toronto

time.sleep(5)

print('city' in cache)

False