'Get the next stanza that has been \'sent\'.
Arguments:
timeout -- Optional timeout for waiting for a new value.'

def next_sent(self, timeout=None):

    args = {'block': False}
    if (timeout is not None):
        args = {'block': True, 'timeout': timeout}
    try:
        return self.send_queue.get(**args)
    except:
        return None
