Update bitsandbytes/autograd/_functions.py

Co-authored-by: Aarni Koskela <[email protected]>

Author: matthewdouglas

bitsandbytes/autograd/_functions.py

@@ -291,7 +291,7 @@ def forward(
         B: torch.Tensor,
         out=None,
         bias: Optional[torch.Tensor] = None,
-        state: MatmulLtState = None,
+        state: Optional[MatmulLtState] = None,
     ):
         state = state or MatmulLtState()