diff --git a/third_party/2/werkzeug/datastructures.pyi b/third_party/2/werkzeug/datastructures.pyi
index 7becae0a6..cbbddf940 100644
--- a/third_party/2/werkzeug/datastructures.pyi
+++ b/third_party/2/werkzeug/datastructures.pyi
@@ -161,7 +161,7 @@ class Headers(Mapping):
     def __copy__(self): ...
 
 class ImmutableHeadersMixin:
-    def __delitem__(self, key, **kwargs): ...
+    def __delitem__(self, key, _index_operation=True): ...  # FIXME: This is invalid but works around https://github.com/pallets/werkzeug/issues/1051
     def __setitem__(self, key, value): ...
     set = ...  # type: Any
     def add(self, *args, **kwargs): ...