counts = {}
def allow(key, now):
    window = now // 60
    bucket = (key, window)
    counts[bucket] = counts.get(bucket, 0) + 1
    return counts[bucket] <= 3
assert [allow("demo", 10) for _ in range(4)] == [True, True, True, False]
assert allow("demo", 60)
print("fourth attempt denied; next window allowed")