[fix] Fix Black formatting in invalidate_controller_views_for_group #1070

Author: mn-ram

openwisp_controller/config/tasks.py

@@ -231,7 +231,5 @@ def invalidate_controller_views_for_group(group_id):
 
     Device = load_model("config", "Device")
 
-    for device in (
-        Device.objects.filter(group_id=group_id).only("id").iterator()
-    ):
+    for device in Device.objects.filter(group_id=group_id).only("id").iterator():
         DeviceChecksumView.invalidate_get_device_cache(device)