Create revocation registry and new tails file (and association to
        corresponding revocation registry definition via symbolic link) for input
        revocation registry identifier.

        :param rr_id: revocation registry identifier
        :param rr_size: revocation registry size (defaults to 256)

async def _create_rev_reg(self, rr_id: str, rr_size: int = None) -> None:
        """
        Create revocation registry and new tails file (and association to
        corresponding revocation registry definition via symbolic link) for input
        revocation registry identifier.

        :param rr_id: revocation registry identifier
        :param rr_size: revocation registry size (defaults to 256)
        """

        LOGGER.debug('Issuer._create_rev_reg >>> rr_id: %s, rr_size: %s', rr_id, rr_size)

        rr_size = rr_size or 256
        (cd_id, tag) = rev_reg_id2cred_def_id__tag(rr_id)

        LOGGER.info('Creating revocation registry (capacity %s) for rev reg id %s', rr_size, rr_id)
        tails_writer_handle = await blob_storage.open_writer(
            'default',
            json.dumps({
                'base_dir': Tails.dir(self._dir_tails, rr_id),
                'uri_pattern': ''
            }))
        apriori = Tails.unlinked(self._dir_tails)
        (rr_id, rrd_json, rre_json) = await anoncreds.issuer_create_and_store_revoc_reg(
            self.wallet.handle,
            self.did,
            'CL_ACCUM',
            tag,
            cd_id,
            json.dumps({
                'max_cred_num': rr_size,
                'issuance_type': 'ISSUANCE_ON_DEMAND'
            }),
            tails_writer_handle)
        delta = Tails.unlinked(self._dir_tails) - apriori
        if len(delta) != 1:
            LOGGER.debug(
                'Issuer._create_rev_reg: <!< Could not create tails file for rev reg id: %s', rr_id)
            raise CorruptTails('Could not create tails file for rev reg id {}'.format(rr_id))
        tails_hash = basename(delta.pop())
        Tails.associate(self._dir_tails, rr_id, tails_hash)

        with REVO_CACHE.lock:
            rrd_req_json = await ledger.build_revoc_reg_def_request(self.did, rrd_json)
            await self._sign_submit(rrd_req_json)
            await self._get_rev_reg_def(rr_id)  # add to cache en passant

        rre_req_json = await ledger.build_revoc_reg_entry_request(self.did, rr_id, 'CL_ACCUM', rre_json)
        await self._sign_submit(rre_req_json)

        LOGGER.debug('Issuer._create_rev_reg <<<')