상속: IExecuteSystem
 Systems createSameInstance()
 {
     var system = new RandomDurationSystem();
     return new Feature("Same System Instances")
         .Add(system)
         .Add(system)
         .Add(system);
 }
    Systems createSameInstance()
    {
        var system = new RandomDurationSystem();

        return(new Feature("Same System Instances")
               .Add(system)
               .Add(system)
               .Add(system));
    }