import time, random

def with_backoff(fn, attempts=5):
    for i in range(attempts):
        try:
            return fn()
        except Exception as e:
            status = getattr(e, 'status_code', None)
            if status not in (429, 500, 502, 503, 529) or i == attempts - 1:
                raise
            # full jitter: avoids a thundering herd on recovery
            time.sleep(random.uniform(0, 2 ** i))