diff --git a/Tests/test_file_png.py b/Tests/test_file_png.py
index 5bfbbbab8..a3669ef5a 100644
--- a/Tests/test_file_png.py
+++ b/Tests/test_file_png.py
@@ -99,18 +99,27 @@ class TestFilePng:
                 if mode == "I;16":
                     reloaded = reloaded.convert(mode)
                 assert_image_equal(reloaded, im)
-    
+
     def test_putpalette(self):
         valid_file = "Tests/images/FudanPed00003_mask.png"
         with pytest.raises(ValueError) as err:
             mask = Image.open(valid_file)
-            mask.putpalette([
-                0, 0, 0, # black background
-                255, 0, 0, # index 1 is red
-                255, 255, 0, # index 2 is yellow
-                255, 153, 0, # index 3 is orange
-            ])
-
+            mask.putpalette(
+                [
+                    0,
+                    0,
+                    0,  # black background
+                    255,
+                    0,
+                    0,  # index 1 is red
+                    255,
+                    255,
+                    0,  # index 2 is yellow
+                    255,
+                    153,
+                    0,  # index 3 is orange
+                ]
+            )
 
     def test_invalid_file(self):
         invalid_file = "Tests/images/flower.jpg"