anchor.diff:      deleteUsernameFromDevice();
       var box = await Hive.openBox<AuthenticationModel>('AuthenticationModel');
       await box.clear();
  -    deactivateStudentCards();
       print('logged out');
       _isLoading = false;
       notifyListeners();
  
positive.code: 
    List<String> _notificationsSettings;
  
    activateStudentCards() {
      int index = _cardOrder.indexOf('MyStudentChart') + 1;
      for (String card in _studentCards) {
        _cardStates[card] = true;
      }
      _cardOrder.insertAll(index, _studentCards.toList());
    }
  
    deactivateStudentCards() {
      for (String card in _studentCards) {
        _cardStates[card] = false;
        _cardOrder.remove(card);
      }
    }
  
    ///Update the authentication model saved in state and save the model in persistent storage
    Future updateAuthenticationModel(AuthenticationModel model) async {
      _authenticationModel = model;
  
negative.code:           base64.encode(utf8.encode(username + ':' + encryptedPassword));
        if (await _authenticationService
            .login(base64EncodedWithEncryptedPassword)) {
          updateAuthenticationModel(_authenticationService.data);
          _pushNotificationDataProvider
              .registerDevice(_authenticationService.data.accessToken);
  