anchor.diff:                          cvmfs_app_util:get_max_lease_time()).
   
   
  --spec get_token_id(Token) -> {ok, PublicId} | {error, invalid_macaroon}
  +-spec get_token_id(Token) -> {ok, PublicId} | {error, {invalid_macaroon,
  +                                                       worker_died}}
                                    when Token :: binary(),
                                         PublicId :: binary().
   get_token_id(Token) ->
  
positive.code:                              invalid_lease |
                               invalid_key |
                               invalid_macaroon |
                               worker_timeout |
                               path_violation |
                               other_error}.
  
negative.code:     gen_server:start_link(?MODULE, Args, []).
  
  
  -spec generate_token(KeyId, Path, MaxLeaseTime) -> {Token, Public, Secret} |
                                                     {error, worker_died}
                                                         when KeyId :: binary(),
                                                              Path :: binary(),
                                                              MaxLeaseTime :: integer(),
  