diff --git a/third_party/2/six/__init__.pyi b/third_party/2/six/__init__.pyi
index c4c4723f8..bd8d97a37 100644
--- a/third_party/2/six/__init__.pyi
+++ b/third_party/2/six/__init__.pyi
@@ -82,7 +82,7 @@ def assertRegex(self: unittest.TestCase, text: AnyStr, expected_regex: Union[Any
 
 def reraise(tp: Optional[Type[BaseException]], value: Optional[BaseException], tb: Optional[types.TracebackType] = ...) -> NoReturn: ...
 def exec_(_code_: Union[unicode, types.CodeType], _globs_: Dict[str, Any] = ..., _locs_: Dict[str, Any] = ...): ...
-def raise_from(value: BaseException, from_value: BaseException) -> None: ...
+def raise_from(value: BaseException, from_value: Optional[BaseException]) -> NoReturn: ...
 
 print_ = print
 
diff --git a/third_party/3/six/__init__.pyi b/third_party/3/six/__init__.pyi
index 80f6766b1..0631a6924 100644
--- a/third_party/3/six/__init__.pyi
+++ b/third_party/3/six/__init__.pyi
@@ -94,7 +94,7 @@ def assertRegex(self: unittest.TestCase, text: AnyStr, expected_regex: Union[Any
 exec_ = exec
 
 def reraise(tp: Optional[Type[BaseException]], value: Optional[BaseException], tb: Optional[types.TracebackType] = None) -> NoReturn: ...
-def raise_from(value: BaseException, from_value: BaseException) -> None: ...
+def raise_from(value: BaseException, from_value: Optional[BaseException]) -> NoReturn: ...
 
 print_ = print