update typehint (#1740)

* update typehint

Signed-off-by: Masaki Kozuki <[email protected]>

* Update float8_linear_utils.py

---------

Signed-off-by: Masaki Kozuki <[email protected]>
Co-authored-by: Mark Saroufim <[email protected]>

Author: 2 people

torchao/float8/float8_linear_utils.py

@@ -85,7 +85,7 @@ def convert_to_float8_training(
     module: nn.Module,
     *,
     module_filter_fn: Optional[Callable[[nn.Module, str], bool]] = None,
-    config: Float8LinearConfig = None,
+    config: Optional[Float8LinearConfig] = None,
 ) -> nn.Module:
     """
     Swaps `torch.nn.Linear` in `module` with `Float8Linear`.