/**
  * The url to the page with the member group edit/create form
  * @param Membergroup $group If member group is given, form page will be in edit mode, otherwise in create mode
  * @return string Returns the form page url
  */
 protected function FormUrl(Membergroup $group = null)
 {
     $args = array();
     if ($group) {
         $args['membergroup'] = $group->GetID();
     }
     return BackendRouter::ModuleUrl(new MembergroupForm(), $args);
 }