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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 _update_record(self, identifier, rtype=None, name=None, content=None):
 """ update a record :param int identifier: identifier of record to update :param str rtype: type of record :param str name: name of record :param mixed content: value of record :return bool: success status :raises Exception: on error """

        record_ids = []
        if not identifier:
            records = self._list_records(rtype, name)
            record_ids = [record['id'] for record in records]
        else:
            record_ids.append(identifier)

        for an_identifier in record_ids:
            opts = {'id': an_identifier}
            if rtype is not None:
                opts['type'] = rtype.upper()
            if name is not None:
                opts['name'] = self._full_name(name)
            if content is not None:
                opts['content'] = content
            opts.update(self._auth)

            response = self._api.nameserver.updateRecord(opts)
            self._validate_response(
                response=response, message='Failed to update record',
                exclude_code=2302)

        return True