Ratelimit in Python and Redis

ratelimit.py

import redis

r = redis.Redis()

def ratelimit(key):
    EXPIRE = 10
    RATE = 10
    
    value = r.incr(str(key))
    
    if value == 1 or r.ttl(str(key)) is None:
        r.expire(str(key), EXPIRE)
    if value > RATE:
        raise Exception('Overflow')