IMapIterator stuck?

[yywing]

I review billiard/pool.py line 1957, and I found:

self._cond = threading.Condition(threading.Lock())
......
self._lost_worker_timeout = lost_worker_timeout
......
def next(self, timeout=None):
    with self._cond:
            ......
            self._cond.wait(timeout)
            ......

self._cond.wait not set timeout. Is it stuck in this place ?

maybe related https://github.com/celery/celery/issues/4185