use f-string

inventory_provider/tasks/worker.py

@@ -180,8 +180,8 @@ def update_interfaces_to_services(self):
     interface_services = defaultdict(list)
     with db.connection(InventoryTask.config["ops-db"]) as cx:
         for service in opsdb.get_circuits(cx):
-            equipment_interface = '%s:%s' % (
-                service['equipment'], service['interface_name'])
+            equipment_interface \
+                = f'{service["equipment"]}:{service["interface_name"]}'
             interface_services[equipment_interface].append(service)
 
     r = get_next_redis(InventoryTask.config)