From 882daa802aa13b460fd59d24952d34fa79d5ad98 Mon Sep 17 00:00:00 2001
From: libaojiang <2461443384@qq.com>
Date: Mon, 12 Oct 2026 23:01:18 +0800
Subject: [PATCH] chore(vertex_ai): annotate Final on base64 padding in
 signature check

The type discipline gate now counts LIT010 against the merge-base
ceiling and the rebase carried one un-annotated assignment over.
---
 litellm/litellm_core_utils/prompt_templates/factory.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/litellm/litellm_core_utils/prompt_templates/factory.py b/litellm/litellm_core_utils/prompt_templates/factory.py
index 559814cbea0..33e2bf03578 100644
--- a/litellm/litellm_core_utils/prompt_templates/factory.py
+++ b/litellm/litellm_core_utils/prompt_templates/factory.py
@@ -1258,7 +1258,7 @@ def _is_valid_thought_signature(signature: str) -> bool:
     if not signature:
         return False
     try:
-        padding = "=" * (-len(signature) % 4)
+        padding: Final = "=" * (-len(signature) % 4)
         base64.b64decode(signature + padding, validate=True)
     except (binascii.Error, ValueError):
         return False