the python document say Condition work will Locks, like RLock...

but i find it not work with Semaphore, because Condition._is_owned is like this

    def _is_owned(self):
        # Return True if lock is owned by current_thread.
        # This method is called only if _lock doesn't have _is_owned().
        if self._lock.acquire(0):
            self._lock.release()
            return False
        else:
            return True

this work for RLock, but not work for Semaphore, and Semaphore do not have it's own _is_owned implement.

i spend a lot of time on this issue. maybe fix it, or document it out?