/**
  * Get the data
  * If a revision-id was specified in the URL we load the revision and not the actual data.
  */
 private function getData()
 {
     // get the record
     $this->record = (array) BackendAgendaModel::getSubscription($this->id);
     // no item found, throw an exceptions, because somebody is f*****g with our URL
     if (empty($this->record)) {
         $this->redirect(BackendModel::createURLForAction('index') . '&error=non-existing');
     }
 }