use f-string

inventory_provider/tasks/worker.py

@@ -717,7 +717,7 @@ def _build_subnet_db(update_callback=lambda s: None):
 
     rp = r.pipeline()
     for k, v in subnets.items():
-        rp.set('subnets:' + k, json.dumps(v))
+        rp.set(f'subnets:{k}', json.dumps(v))
     rp.execute()