> It was a bit more involved than I originally anticipated, as I had to make a minor change in the _worker() function to allow the new parameter to be compatible with wait (which is important, as it prevents dangling threads).

Never mind, I just realized that I could simply add work_queue.put(None) at the end of the queue drain to unblock the indefinitely hanging thread. So, the global constant and change in logic for _worker() isn't needed.