diff --git a/libcst/codemod/commands/convert_type_comments.py b/libcst/codemod/commands/convert_type_comments.py
index cea5c408a..7da1378d1 100644
--- a/libcst/codemod/commands/convert_type_comments.py
+++ b/libcst/codemod/commands/convert_type_comments.py
@@ -811,7 +811,7 @@ def leave_ClassDef(
         self,
         original_node: cst.ClassDef,
         updated_node: cst.ClassDef,
-    ) -> None:
+    ) -> cst.ClassDef:
         """
         Keep track of when we are and are not inside of classes, to help with
         heuristics to handle methods correctly.