anchor.diff:  %% uri of the client "ready" callback with the tmp token and a verifier query
   %% params.
   %% @end
  --spec authorize(oauth1_credentials:id(tmp)) ->
  -    oauth1_uri:t().
  -authorize(_TempCreds) ->
  -    ?not_implemented.
  +-spec authorize(TmpToken :: binary()) ->
  +    hope_result:t(Ok, Error)
  +    when Ok    :: oauth1_uri:t()
  +       , Error :: oauth1_storage:error()
  +                | error()
  +       .
  +authorize(<<TmpTokenID/binary>>) ->
  +    TmpToken = {tmp, TmpTokenID},
  +    case oauth1_credentials:fetch(TmpToken)
  +    of  {error, not_found} ->
  +            {error, {unauthorized, token_invalid}}
  +    ;   {error, _}=Error ->
  +            Error
  +    ;   {ok, _TmpCredentials} ->
  +            case oauth1_callback:fetch(TmpTokenID)
  +            of  {error, not_found} ->
  +                    error("No callback found for a valid tmp token!")
  +            ;   {error, _}=Error ->
  +                    Error
  +            ;   {ok, Callback1} ->
  +                    Verifier = oauth1_verifier:generate(TmpToken),
  +                    case oauth1_verifier:store(Verifier)
  +                    of  {error, _}=Error ->
  +                            Error
  +                    ;   {ok, ok} ->
  +                            Callback2 = oauth1_callback:set_verifier( Callback1
  +                                                                    , Verifier
  +                                                                    ),
  +                            oauth1_callback:get_uri(Callback2)
  +                    end
  +            end
  +    end.
   
   %% @doc Grant the real access token.
   %% @end
  
positive.code:       {bad_request  , error_bad_request()}
      | {unauthorized , error_unauthorized()}
      .
  
  -type authorization_verifier() ::
      boolean().
  
  -type args_initiate() ::
      #oauth1_server_args_initiate{}.
  
negative.code: 
  -export_type(
      [ error/0
      , args_initiate/0
      , args_token/0
      , args_validate_resource_request/0
  