anchor.diff:      }
     }
   
  +  /// iterates through passed in topics list
  +  /// invokes [unsubscribeFromTopic] on firebase object [_fcm]
     void _unsubscribeToTopics(List<String> topics) {
       for (String topic in topics) {
         if ((topic ?? "").isNotEmpty) {
  
positive.code:   /// get all public topics
    List<String> publicTopics() {
      List<String> topicsToReturn = List<String>();
      for (TopicsModel model in _notificationService.topicsModel) {
        if (model.audienceId == 'all') {
          for (Topic topic in model.topics) {
            topicsToReturn.add(topic.topicId);
  
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) {
  