multiprocessing.Queue has no `task_done()`

See https://docs.python.org/2/library/multiprocessing.html#pipes-and-queues

Specifically:

"The Queue, multiprocessing.queues.SimpleQueue and JoinableQueue types are multi-producer, multi-consumer FIFO queues modelled on the Queue.Queue class in the standard library. They differ in that Queue lacks the task_done() and join() methods introduced into Python 2.5’s Queue.Queue class."