def make_source items class TaskSource object def __init__ self items

def make_source(items):
    class TaskSource(object):
        def __init__(self, items):
            self.lock = threading.Lock()
            self.gen = itertools.chain(items, itertools.repeat(None))

        def get(self):
            self.lock.acquire()
            item = self.gen.next()
            self.lock.release()
            return item

    return TaskSource(items)