def _guess_record(self, rtype, name=None, content=None):
        """Tries to find existing unique record by type, name and content"""
        records = self._list_records_internal(
            identifier=None, rtype=rtype, name=name, content=content)
        if len(records) == 1:
            return records[0]
        if len(records) > 1:
            raise Exception(
                'Identifier was not provided and several existing '
                'records match the request for {0}/{1}'.format(rtype, name))
        raise Exception(
            'Identifier was not provided and no existing records match '
            'the request for {0}/{1}'.format(rtype, name))
Tries to find existing unique record by type, name and content