Add TODO comment

tailbone/views/master.py

@@ -652,6 +652,7 @@ class MasterView(View):
         Fetch the current model instance by inspecting the route kwargs and
         doing a database lookup.  If the instance cannot be found, raises 404.
         """
+        # TODO: this can't handle composite model key..is that needed?
         key = self.request.matchdict[self.get_model_key()]
         instance = self.Session.query(self.get_model_class()).get(key)
         if not instance: