diff --git a/tests/device_tests/test_msg_backup_device.py b/tests/device_tests/test_msg_backup_device.py
index 463f32cde..1cce57d96 100644
--- a/tests/device_tests/test_msg_backup_device.py
+++ b/tests/device_tests/test_msg_backup_device.py
@@ -138,7 +138,10 @@ def test_backup_slip39_custom(client: Client, share_threshold, share_count):
     assert client.features.no_backup is False
 
     assert len(IF.mnemonics) == share_count
-    assert shamir.combine_mnemonics(IF.mnemonics[-share_threshold:]).hex() == MNEMONIC_SLIP39_CUSTOM_SECRET
+    assert (
+        shamir.combine_mnemonics(IF.mnemonics[-share_threshold:]).hex()
+        == MNEMONIC_SLIP39_CUSTOM_SECRET
+    )
 
 
 # we only test this with bip39 because the code path is always the same