diff --git a/stdlib/2and3/argparse.pyi b/stdlib/2and3/argparse.pyi
index 32b734c67..627426d9a 100644
--- a/stdlib/2and3/argparse.pyi
+++ b/stdlib/2and3/argparse.pyi
@@ -143,6 +143,7 @@ class _ArgumentGroup:
                      metavar: Union[str, Tuple[str, ...]] = ...,
                      dest: str = ...,
                      version: str = ...) -> None: ...
+    def add_mutually_exclusive_group(self, required: bool = ...) -> _MutuallyExclusiveGroup: ...
 
 class _MutuallyExclusiveGroup(_ArgumentGroup): ...