diff --git a/radicale/app/base.py b/radicale/app/base.py
index f4a37025..e946bffc 100644
--- a/radicale/app/base.py
+++ b/radicale/app/base.py
@@ -38,6 +38,7 @@ class ApplicationBase:
     _rights: rights.BaseRights
     _web: web.BaseWeb
     _encoding: str
+    _permit_delete_collection: bool
     _hook: hook.BaseHook
 
     def __init__(self, configuration: config.Configuration) -> None: