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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 code(self, value):
 """ Set the code of the message. :type value: Codes :param value: the code :raise AttributeError: if value is not a valid code """

        if value not in list(defines.Codes.LIST.keys()) and value is not None:
            raise AttributeError
        self._code = value