private function handleCompleted($data)
 {
     $group = GroupBackend::fetch_group_profile($this->params['id']);
     $assignments = [];
     foreach (GroupBackend::fetch_group_users($group) as $user) {
         foreach (UserBackend::fetch_user_assignments_complete($user) as $assignment) {
             $assignments[$assignment["assignment"]["assignment-id"]] = $assignment["assignment"];
         }
     }
     $completed = [];
     foreach ($assignments as $assignment) {
         $completed[] = $assignment;
     }
     return ["assignments" => $completed];
 }
 private function handleCompleted($data)
 {
     return UserBackend::fetch_user_assignments_complete(UserBackend::fetch_user_profile($this->params['id']));
 }