diff --git a/python-package/lightgbm/engine.py b/python-package/lightgbm/engine.py
index 898dbb91a16e..ccbb4376a89f 100644
--- a/python-package/lightgbm/engine.py
+++ b/python-package/lightgbm/engine.py
@@ -605,10 +605,7 @@ def _agg_cv_result(
     # [
     #     (<dataset_name>, <metric_name>, mean(<values>), <is_higher_better>, std_dev(<values>))
     # ]
-    return [
-        (k[0], k[1], float(np.mean(v)), metric_types[k], float(np.std(v)))
-        for k, v in metric_values.items()
-    ]
+    return [(k[0], k[1], float(np.mean(v)), metric_types[k], float(np.std(v))) for k, v in metric_values.items()]
 
 
 def cv(