diff --git a/third_party/2and3/pyre_extensions.pyi b/third_party/2and3/pyre_extensions.pyi
index 04adc5093..c6c4fd869 100644
--- a/third_party/2and3/pyre_extensions.pyi
+++ b/third_party/2and3/pyre_extensions.pyi
@@ -1,6 +1,7 @@
-from typing import List, Optional, Type, TypeVar
+from typing import Any, List, Optional, Type, TypeVar
 
 _T = TypeVar("_T")
 
-def none_throws(optional: Optional[_T]) -> _T: ...
+def none_throws(optional: Optional[_T], message: str = ...) -> _T: ...
+def safe_cast(new_type: Type[_T], value: Any) -> _T: ...
 def ParameterSpecification(__name: str) -> List[Type]: ...