anchor.diff:          }
         }
         _topicSubscriptionState = newTopics;
  -    }
  -  }
  -
  +      _topicsModel = _notificationService.topicsModel;
  +    } else {
  +      _error = 'failed to fetch topics';
  +    }
  +    notifyListeners();
  +  }
  +
  +  /// reads android device info
  +  /// returns info as a Map
     Map<String, dynamic> _readAndroidBuildData(AndroidDeviceInfo build) {
       return <String, dynamic>{
         'version.securityPatch': build.version.securityPatch,
  
positive.code:     notifyListeners();
    }
  
    void _subscribeToTopics(List<String> topics) {
      for (String topic in topics) {
        if ((topic ?? "").isNotEmpty) {
  
negative.code:   FirebaseMessaging _fcm;
    DeviceInfoPlugin deviceInfoPlugin;
    Map<String, dynamic> _deviceData = <String, dynamic>{};
  
    ///STATES
    DateTime _lastUpdated;
    String _error;
    List<TopicsModel> _topicsModel;
    Map<String, bool> _topicSubscriptionState = <String, bool>{};
  
    ///SERVICES
    NotificationService _notificationService;
  
    /// invokes correct method to receive device info
    /// invokes [fetchTopicsList]
    initState() async {
      fetchTopicsList();
      if (Platform.isAndroid) {
  