def _get_matching_dns_entry_ids(self, identifier=None, rtype=None,
                                    name=None, content=None):
        """Return a list of DNS entries that match the given criteria."""
        record_ids = []
        if not identifier:
            records = self._list_records(rtype, name, content)
            record_ids = [record['id'] for record in records]
        else:
            record_ids.append(identifier)
        return record_ids
Return a list of DNS entries that match the given criteria.