/* create a map of Notifier UUIDs and/or names to Notifiers */
 protected Map<Object, Notifier> getNotifierMap(Map payloads) throws Exception {
   Map<Object, Notifier> notifiers = new HashMap<Object, Notifier>(payloads.size() * 2);
   for (Object id : payloads.keySet()) {
     Identifier identifier = Identifier.from(id);
     Notifier notifier;
     if (identifier.isUUID()) {
       notifier = em.get(identifier.getUUID(), Notifier.class);
     } else {
       EntityRef ref = em.getAlias("notifier", identifier.getName());
       notifier = em.get(ref, Notifier.class);
     }
     if (notifier != null) {
       notifiers.put(notifier.getUuid(), notifier);
       notifiers.put(notifier.getUuid().toString(), notifier);
       if (notifier.getName() != null) {
         notifiers.put(notifier.getName(), notifier);
       }
     }
   }
   return notifiers;
 }