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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 add_consumer_tag(self, tag):
 """Add a Consumer tag. :param str tag: Consumer tag. :return: """

        if not is_string(tag):
            raise AMQPChannelError('consumer tag needs to be a string')
        if tag not in self._consumer_tags:
            self._consumer_tags.append(tag)