anchor.diff:  }
   
   class Room extends Card {
  -  final String room;
  -  
  -  const Room._(this.room);
  +  const Room._(this.name);
     
     static final Room HALL =
         const Room._("HALL");
  
positive.code: 
  
  abstract class Card {
    const Card();
  }
  
  class Character extends Card {
    final String character; 
    
    const Character._(this.character);
    
    static final Character SCARLET =
        const Character._("SCARLET");
  
negative.code: }
  
  class Weapon extends Card {
    const Weapon._(this.name);
    static final Weapon KNIFE =
        const Weapon._("KNIFE");
    static final Weapon CANDLESTICK =
  