public static class EventAggregatorExtensions
  {
    public static void Subscribe(this IEventAggregator eventAggregator, params IHandle[] handlers)
    {
      Subscribe(eventAggregator, (IEnumerable<IHandle>)handlers);
    }

    public static void Subscribe(this IEventAggregator eventAggregator, IEnumerable<IHandle> handlers)
    {
      foreach(var handler in handlers)
      {
        if(handler != null)
          eventAggregator.Subscribe(handler);
      }
    }
  }