diff --git a/third_party/2and3/google/protobuf/message.pyi b/third_party/2and3/google/protobuf/message.pyi
index 76ec3d9d2..3fc8c33d2 100644
--- a/third_party/2and3/google/protobuf/message.pyi
+++ b/third_party/2and3/google/protobuf/message.pyi
@@ -25,8 +25,8 @@ class Message:
     def IsInitialized(self) -> bool: ...
     def MergeFromString(self, serialized: Any) -> int: ...  # TODO: we need to be able to call buffer() on serialized
     def ParseFromString(self, serialized: Any) -> None: ...
-    def SerializeToString(self) -> bytes: ...
-    def SerializePartialToString(self) -> bytes: ...
+    def SerializeToString(self, deterministic: bool = ...) -> bytes: ...
+    def SerializePartialToString(self, deterministic: bool = ...) -> bytes: ...
     def ListFields(self) -> Sequence[Tuple[FieldDescriptor, Any]]: ...
     def HasField(self, field_name: Text) -> bool: ...
     def ClearField(self, field_name: Text) -> None: ...