public MediatorManager(SubscribableManager subscribable_manager)
 {
     SubscribableManager = subscribable_manager;
     NotifiableManager = new NotifiableManager();
 }
 public MediatorManager(SubscribableManager subscribable_manager, NotifiableManager notifiable_manager)
 {
     SubscribableManager = subscribable_manager;
     NotifiableManager = notifiable_manager;
 }