DiceStickers.fromJson constructor
a DiceStickers return type can be :
Implementation
factory DiceStickers.fromJson(Map<String, dynamic> json) {
  switch (json["@type"]) {
    case DiceStickersRegular.CONSTRUCTOR:
      return DiceStickersRegular.fromJson(json);
    case DiceStickersSlotMachine.CONSTRUCTOR:
      return DiceStickersSlotMachine.fromJson(json);
    default:
      return const DiceStickers();
  }
}