Generator function which yields ResourceRecordSet for the managed
            gcloud zone, until there are no more records to pull.

            :param gcloud_zone: zone to pull records from
            :type gcloud_zone: google.cloud.dns.ManagedZone
            :param page_token: page token for the page to get

            :return: a resource record set
            :type return: google.cloud.dns.ResourceRecordSet

def _get_gcloud_records(self, gcloud_zone, page_token=None):
        """ Generator function which yields ResourceRecordSet for the managed
            gcloud zone, until there are no more records to pull.

            :param gcloud_zone: zone to pull records from
            :type gcloud_zone: google.cloud.dns.ManagedZone
            :param page_token: page token for the page to get

            :return: a resource record set
            :type return: google.cloud.dns.ResourceRecordSet
        """
        gcloud_iterator = gcloud_zone.list_resource_record_sets(
            page_token=page_token)
        for gcloud_record in gcloud_iterator:
            yield gcloud_record
        # This is to get results which may be on a "paged" page.
        # (if more than max_results) entries.
        if gcloud_iterator.next_page_token:
            for gcloud_record in self._get_gcloud_records(
                    gcloud_zone, gcloud_iterator.next_page_token):
                # yield from is in python 3 only.
                yield gcloud_record