diff --git a/monai/transforms/regularization/array.py b/monai/transforms/regularization/array.py
index 6c9022d647..0b495c8623 100644
--- a/monai/transforms/regularization/array.py
+++ b/monai/transforms/regularization/array.py
@@ -22,6 +22,7 @@
 
 
 class Mixer(RandomizableTransform):
+
     def __init__(self, batch_size: int, alpha: float = 1.0) -> None:
         """
         Mixer is a base class providing the basic logic for the mixup-class of
diff --git a/tests/test_regularization.py b/tests/test_regularization.py
index d381ea72ca..22faf1027d 100644
--- a/tests/test_regularization.py
+++ b/tests/test_regularization.py
@@ -19,6 +19,7 @@
 
 
 class TestMixup(unittest.TestCase):
+
     def test_mixup(self):
         for dims in [2, 3]:
             shape = (6, 3) + (32,) * dims
@@ -52,6 +53,7 @@ def test_mixupd(self):
 
 
 class TestCutMix(unittest.TestCase):
+
     def test_cutmix(self):
         for dims in [2, 3]:
             shape = (6, 3) + (32,) * dims
@@ -76,6 +78,7 @@ def test_cutmixd(self):
 
 
 class TestCutOut(unittest.TestCase):
+
     def test_cutout(self):
         for dims in [2, 3]:
             shape = (6, 3) + (32,) * dims