diff --git a/stdlib/3/inspect.pyi b/stdlib/3/inspect.pyi
index 65fe700c3..9696067cc 100644
--- a/stdlib/3/inspect.pyi
+++ b/stdlib/3/inspect.pyi
@@ -175,8 +175,8 @@ def getclasstree(classes: List[type], unique: bool = ...) -> Any: ...
 
 class ArgSpec(NamedTuple):
     args: List[str]
-    varargs: str
-    keywords: str
+    varargs: Optional[str]
+    keywords: Optional[str]
     defaults: Tuple[Any, ...]
 
 class Arguments(NamedTuple):