anchor.diff:      Issuer = << <<"rsp-">>/binary, I/binary >>,
       {Issuer, S}.
   
  -get_return_url(#watts_rsp{ use_referer = true,
  -                           session = #watts_rsp_session{ referer = R }}) ->
  +get_return_url(#watts_rsp{session = Session}) ->
  +    session_return_url(Session).
  +
  +session_return_url(#watts_rsp_session{ referer = R, success_url = undefined }) ->
       R;
  -get_return_url(#watts_rsp{ use_referer = false, return_url = Url}) ->
  -    Url.
  +session_return_url(#watts_rsp_session{ success_url = R }) ->
  +    R.
  +
   
   get_service_data(#watts_rsp{ session = #watts_rsp_session{ service_id = Id,
                                                              params = Param}}) ->
  
positive.code: 
  -record(watts_rsp_session, {
            referer = undefined,
            iss = undefined,
            sub = undefined,
            service_id = undefined,
  
negative.code:                  service_id = ServiceId,
                   params = Params,
                   provider = Provider,
                   success_url = Success,
                   failed_url = Failed,
                   referer = Referer
                  },
      {ok, Rsp#watts_rsp{session = Session}};
  