diff --git a/tests/test_download_progress.py b/tests/test_download_progress.py
index 511cbc5..ecc0494 100644
--- a/tests/test_download_progress.py
+++ b/tests/test_download_progress.py
@@ -7,6 +7,9 @@ from whisper_local.tray._download_progress import TkProgressTqdm
 
 
 class TestTkProgressTqdm:
+    def teardown_method(self):
+        TkProgressTqdm._queue = None
+
     def test_update_puts_message_in_queue(self):
         q = queue.Queue()
         TkProgressTqdm._queue = q
diff --git a/whisper_local/tray/_download_progress.py b/whisper_local/tray/_download_progress.py
index 37b558f..3b6d055 100644
--- a/whisper_local/tray/_download_progress.py
+++ b/whisper_local/tray/_download_progress.py
@@ -20,7 +20,9 @@ class TkProgressTqdm(tqdm_module.tqdm):
         self._accumulated_n = 0
         super().__init__(*args, **kwargs)
 
-    def update(self, n: int = 1) -> bool | None:
+    def update(self, n: int | float | None = 1) -> bool | None:
+        if n is None:
+            n = 0
         self._accumulated_n += n
         result = super().update(n)
         if self._queue is not None: