diff --git a/stdlib/3/traceback.pyi b/stdlib/3/traceback.pyi
index d556ec1e7..4abc031c2 100644
--- a/stdlib/3/traceback.pyi
+++ b/stdlib/3/traceback.pyi
@@ -6,7 +6,7 @@ import typing
 
 # TODO signatures
 def format_exception_only(etype, value) -> List[str]: ...
-def format_exception(type: type, value: BaseException, tb: TracebackType, limit: int, chain: bool) -> List[str]: ...
+def format_exception(type: type, value: BaseException, tb: TracebackType, limit: int = ..., chain: bool = ...) -> List[str]: ...
 def format_tb(traceback): ...
 def print_exc(limit=..., file=..., chain=...): ...
 def format_exc(limit: int = ..., chain: bool = ...) -> str: ...