add Map to Map

Map map = {
  "wowo":"mantap",
};
SegmenSingleModel? segmenSingleModel = SegmenSingleModel(message: 'ok',status: true);

segmenSingleModel.toJson().forEach((key, value) {
  map.addAll(segmenSingleModel.toJson());
});
print(map.toString());

How to add a new pair to Map in Dart?Stack Overflow