void Call(string itemName, ModalityMessage command)
 {
     if (subscribers [itemName])
     {
         subscribers [itemName].BroadcastMessage("Modality", command, SendMessageOptions.DontRequireReceiver);
     }
 }
 void Call(string itemName, ModalityMessage command)
 {
     if (subscribers [itemName])
                         subscribers [itemName].BroadcastMessage ("Modality", command, SendMessageOptions.DontRequireReceiver);
 }