# listenTo method Null safety

1. @override

StreamSubscription<SectionModel> listenTo(

1. String documentId,
2. SectionChanged changed,
3. {SectionErrorHandler? errorHandler}

)
override

## Implementation

    @override
    StreamSubscription<SectionModel> listenTo(
        String documentId, SectionChanged changed,
        {SectionErrorHandler? errorHandler}) {
      throw UnimplementedError();
    }