import 'package:json_annotation/json_annotation.dart'; import 'tts_results.dart'; part 'payload.g.dart'; @JsonSerializable() class Payload { @JsonKey(name: 'tts_results') TtsResults? ttsResults; Payload({this.ttsResults}); factory Payload.fromJson(Map json) { return _$PayloadFromJson(json); } Map toJson() => _$PayloadToJson(this); }