def _add_call_item_to_queue(pending_work_items,
                            work_ids,
                            call_queue):
    while True:
        if call_queue.full():
            return
        try:
            work_id = work_ids.get(block=False)
        except queue.Empty:
            return
        else:
            work_item = pending_work_items[work_id]

            if work_item.future.set_running_or_notify_cancel():
                call_queue.put(_CallItem(work_id,
                                         work_item.fn,
                                         work_item.args,
                                         work_item.kwargs),
                               block=True)
            else:
                del pending_work_items[work_id]
                continue
Fills call_queue with _WorkItems from pending_work_items.
dataset/ETHPy150Open SickRage/SickRage/lib/concurrent/futures/process.py/_add_call_item_to_queue