'Retrieve a list of messages from the messages cookie. If the
not_finished sentinel value is found at the end of the message list,
remove it and return a result indicating that not all messages were
retrieved by this storage.'

def _get(self, *args, **kwargs):

    data = self.request.COOKIES.get(self.cookie_name)
    messages = self._decode(data)
    all_retrieved = (not (messages and (messages[(-1)] == self.not_finished)))
    if (messages and (not all_retrieved)):
        messages.pop()
    return (messages, all_retrieved)
