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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 _serialize(self, value, ct):
 """Auto-serialization of the value based upon the content-type value. :param any value: The value to serialize :param ietfparse.: The content type to serialize :rtype: str :raises: ValueError """

        key = '{}/{}'.format(ct.content_type, ct.content_subtype)
        if key not in self._SERIALIZATION_MAP:
            raise ValueError('Unsupported content-type: {}'.format(key))
        elif not self._SERIALIZATION_MAP[key].get('enabled', True):
            self.logger.debug('%s is not enabled in the serialization map',
                              key)
            raise ValueError('Disabled content-type: {}'.format(key))
        return self._maybe_invoke_serialization(
            self._maybe_decode(value, ct.parameters.get('charset', 'utf-8')),
            'dump', key)