#9231 add comment

netbox/netbox/filtersets.py

@@ -81,6 +81,9 @@ class BaseFilterSet(django_filters.FilterSet):
     })
 
     def __init__(self, *args, **kwargs):
+        # bit of a hack for #9231 - extras.lookup.Empty is registered in apps.ready
+        # however FilterSet Factory is setup before this which creates the
+        # initial filters.  This recreates the filters so Empty is picked up correctly.
         self.base_filters = self.__class__.get_filters()
         super().__init__(*args, **kwargs)