diff --git a/parfive/downloader.py b/parfive/downloader.py
index e3290bb..29c3bba 100644
--- a/parfive/downloader.py
+++ b/parfive/downloader.py
@@ -229,7 +229,7 @@ def _add_shutdown_signals(loop, task):
         if threading.current_thread() != threading.main_thread():
             warnings.warn(
                 "This download has been started in a thread which is not the main thread. You will not be able to interrupt the download.",
-                UserWarning
+                UserWarning,
             )
             return
 
diff --git a/parfive/tests/test_downloader.py b/parfive/tests/test_downloader.py
index 5d79e82..6351d70 100644
--- a/parfive/tests/test_downloader.py
+++ b/parfive/tests/test_downloader.py
@@ -474,7 +474,10 @@ def __init__(self, *args, **kwargs):
     def run(self):
         self.result = self._target(*self._args, **self._kwargs)
 
+
 import warnings
+
+
 def test_download_out_of_main_thread(httpserver, tmpdir):
     tmpdir = str(tmpdir)
     httpserver.serve_content(
@@ -486,8 +489,11 @@ def test_download_out_of_main_thread(httpserver, tmpdir):
 
     thread = CustomThread(target=dl.download)
     thread.start()
-   
-    with pytest.warns(UserWarning, match="This download has been started in a thread which is not the main thread. You will not be able to interrupt the download."):    
+
+    with pytest.warns(
+        UserWarning,
+        match="This download has been started in a thread which is not the main thread. You will not be able to interrupt the download.",
+    ):
         thread.join()
 
     validate_test_file(thread.result)