Simplify the event map

installer.sh

@@ -891,7 +891,10 @@ def event_label(event_type):
 
     try:
         with open(LABEL_MAP, 'r') as f:
-            labels = json.load(f) | labels
+            oc_labels = json.load(f)
+            if isinstance(oc_labels, dict):
+                oc_labels.update(labels)
+                labels = oc_labels
     except Exception:
         pass