diff --git a/Tests/test_file_png.py b/Tests/test_file_png.py
index 3b4ffff3ef0..28543c43384 100644
--- a/Tests/test_file_png.py
+++ b/Tests/test_file_png.py
@@ -786,7 +786,7 @@ class TestTruncatedPngPLeaks(PillowLeakTestCase):
     iterations = 100  # Leak is 56k/iteration, this will leak 5.6megs
 
     def test_leak_load(self):
-        files = ['Tests/images/hopper.png', 'Tests/images/end_trunc_file.png']
+        files = ["Tests/images/hopper.png", "Tests/images/end_trunc_file.png"]
         for file in files:
             with open(file, "rb") as f:
                 DATA = BytesIO(f.read(16 * 1024))