bugfix when not user preference class is defined

basetheme_bootstrap/admin.py

@@ -55,7 +55,11 @@ class UserPreferencesAdmin(admin.ModelAdmin):
             "user",
         ]
     ]
-    filter_horizontal = [field.name for field in get_user_preference_class()._meta.get_fields() if field.many_to_many]
+    filter_horizontal = [field.name for field in (
+        []
+        if get_user_preference_class() is None
+        else get_user_preference_class()._meta.get_fields()
+    ) if field.many_to_many]
 
     def username(self, obj):
         return mark_safe("<i>default preferences</i>") if obj.user is None else obj.user

setup.cfg

 [metadata]
 name = django-basetheme-bootstrap
-version = 1.8.5
+version = 1.8.6
 description = Django Basetheme Bootstrap
 long_description = file: README.rst
 url = https://gitlab.pasteur.fr/bbrancot/django-basetheme-bootstrap