class CreateGameResponse { final String? passphrase; const CreateGameResponse({ required this.passphrase, }); factory CreateGameResponse.empty() { return const CreateGameResponse(passphrase: null); } factory CreateGameResponse.fromJson(Map json) { final passphrase = json['passphrase']; return CreateGameResponse(passphrase: passphrase); } Map toJson() { return { 'passphrase': passphrase, }; } }