code: def ok_rev_reg_id(token: str, issuer_did: str = None) -> bool:
      
  
      rr_id_m = re.match(
          '([{0}]{{21,22}}):4:([{0}]{{21,22}}):3:CL:[1-9][0-9]*(:.+)?:CL_ACCUM:.+$'.format(B58),
          token or '')
      return bool(rr_id_m) and ((not issuer_did) or (rr_id_m.group(1) == issuer_did and rr_id_m.group(2) == issuer_did))
docs: Whether input token looks like a valid revocation registry identifier from input issuer DID (default any); i.e.,
      <issuer-did>:4:<issuer-did>:3:CL:<schema-seq-no>:<cred-def-id-tag>:CL_ACCUM:<rev-reg-id-tag> for protocol >= 1.4, or
      <issuer-did>:4:<issuer-did>:3:CL:<schema-seq-no>:CL_ACCUM:<rev-reg-id-tag> for protocol == 1.3.
  
      :param token: candidate string
      :param issuer_did: issuer DID to match, if specified
      :return: whether input token looks like a valid revocation registry identifier