docs: def rev_reg_id2cred_def_id_tag(rr_id: str) -> (str, str):
      """
      Given a revocation registry identifier, return its corresponding credential definition identifier and
      (stringified int) tag. Raise BadIdentifier if input is not a revocation registry identifier.
  
      :param rr_id: revocation registry identifier
      :return: credential definition identifier and tag
      """
  
      if ok_rev_reg_id(rr_id):
          return (
              ':'.join(rr_id.split(':')[2:-2]),  # rev reg id comprises (prefixes):<cred_def_id>:(suffixes)
              str(rr_id.split(':')[-1])  # tag is last token
          )
      raise BadIdentifier('Bad revocation registry identifier {}'.format(rr_id))