From fe48f37bf7ebf293fb971722d39f7ece4a9eb9b8 Mon Sep 17 00:00:00 2001
From: Simon Lanzmich <48890288+slanzmich@users.noreply.github.com>
Date: Sun, 3 Dec 2023 23:46:33 +0100
Subject: [PATCH] stdlib: Annotate `type.__prepare__` to return a mutable
 object (#11093)

During class creation, the namespace returned by `__prepare__` is
populated when the class body is executed. Therefore, it must be
mutable.
---
 stdlib/builtins.pyi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
index 92b5279bc..6d2e219e0 100644
--- a/stdlib/builtins.pyi
+++ b/stdlib/builtins.pyi
@@ -203,7 +203,7 @@ class type:
     def __instancecheck__(self, __instance: Any) -> bool: ...
     def __subclasscheck__(self, __subclass: type) -> bool: ...
     @classmethod
-    def __prepare__(metacls, __name: str, __bases: tuple[type, ...], **kwds: Any) -> Mapping[str, object]: ...
+    def __prepare__(metacls, __name: str, __bases: tuple[type, ...], **kwds: Any) -> MutableMapping[str, object]: ...
     if sys.version_info >= (3, 10):
         def __or__(self, __value: Any) -> types.UnionType: ...
         def __ror__(self, __value: Any) -> types.UnionType: ...