diff --git a/reasoning_gym/arithmetic/bitwise_arithmetic.py b/reasoning_gym/arithmetic/bitwise_arithmetic.py
index 4870beb2..3c0213b1 100644
--- a/reasoning_gym/arithmetic/bitwise_arithmetic.py
+++ b/reasoning_gym/arithmetic/bitwise_arithmetic.py
@@ -123,7 +123,10 @@ class BitwiseArithmeticDataset(ProceduralDataset):
             rng,
             self.config.difficulty,
         )
-        problem_str = f"Please solve this problem. Assume there is arbitrary bit depth and that there are signed integers. Reply only with the final hexidecimal value.\n" + problem
+        problem_str = (
+            f"Please solve this problem. Assume there is arbitrary bit depth and that there are signed integers. Reply only with the final hexidecimal value.\n"
+            + problem
+        )
 
         return {"question": problem_str, "answer": answer, "metadata": {"problem": problem}}