fix style

Author: NoRaincheck

onnxscript/irbuilder.py

@@ -397,7 +397,11 @@ def to_proto(f):
         if "" not in opsets:
             # No operator is using the standard opset.
             # Use the specified version if provided or the default value.
-            opsets[""] = opset_version if opset_version is not None else onnx_opset_version()
+            opsets[""] = (
+                opset_version
+                if opset_version is not None
+                else onnx_opset_version()
+            )
 
         if "ir_version" not in kwargs:
             kwargs["ir_version"] = select_ir_version(opsets[""])