[Dart] 원하는 객체 hash 오버라이딩

class Medicine {
  final String itemName; // 제품명
  final String entpName; // 업체명
  final int count;

  @override
  bool operator==(Object other) =>
      other is Medicine && itemName == other.itemName;

  @override
  int get hashCode => Object.hash(itemName, entpName);

 }