public static CarWithIInvariant Park(this CarWithIInvariant source) { ((Car)source).Parked = true; return(source); }
public static CarWithIInvariant DriveFast(this CarWithIInvariant source) { ((Car)source).DriveFast(); return(source); }
public static CarWithIInvariant DriveFar(this CarWithIInvariant source) { ((Car)source).NeedFuel = true; return(source); }