bugfix: Allow notification only for Model subclasses

djangoldp_notification/models.py

@@ -54,7 +54,7 @@ class Subscription(Model):
 # --- SUBSCRIPTION SYSTEM ---
 @receiver(post_save, dispatch_uid="callback_notif")
 def send_notification(sender, instance, **kwargs):
-    if (sender != Notification and sender != LogEntry and sender != Session and sender != Token):
+    if sender != Notification and isinstance(sender, Model):
         threads = []
         url = settings.BASE_URL + Model.resource_id(instance) + '/'
         for subscription in Subscription.objects.filter(object=url):