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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def list_all_before(self, message_id, limit=None):
 """Return all group messages created before a message. :param str message_id: the ID of a message :param int limit: maximum number of messages per page :return: group messages :rtype: generator """

        return self.list_before(message_id, limit=limit).autopage()