diff --git a/onnxoptimizer/test/optimizer_test.py b/onnxoptimizer/test/optimizer_test.py
index e591b41ae..3c8107a4b 100644
--- a/onnxoptimizer/test/optimizer_test.py
+++ b/onnxoptimizer/test/optimizer_test.py
@@ -4615,7 +4615,7 @@ def test_rewrite_where(self):
             """)
 
         optimized_model = self._optimized(
-            model,["rewrite_where"], True)
+            model, ["rewrite_where"], True)
 
         assert len(optimized_model.graph.node) == 5
         assert set([i.op_type for i in optimized_model.graph.node]) == {'Where', 'And', 'Sign'}
@@ -4623,6 +4623,5 @@ def test_rewrite_where(self):
         assert optimized_model.graph.node[3].input == ['M', 'X', 'Y']
 
 
-
 if __name__ == "__main__":
     unittest.main()