diff --git a/distributed/tests/test_sizeof.py b/distributed/tests/test_sizeof.py
index c54363ecdaa..e0f812b5bd8 100644
--- a/distributed/tests/test_sizeof.py
+++ b/distributed/tests/test_sizeof.py
@@ -24,7 +24,10 @@ def __sizeof__(self):
     with captured_logger("distributed.sizeof") as logs:
         assert safe_sizeof(foo) == 1e6
 
-    assert f"Sizeof calculation for object of type 'test_sizeof.BadlySized' failed. Defaulting to 0.95 MiB" in logs.getvalue()
+    assert (
+        "Sizeof calculation for object of type 'test_sizeof.BadlySized' failed. Defaulting to 0.95 MiB"
+        in logs.getvalue()
+    )
 
     # Can provide custom `default_size`
     with captured_logger("distributed.sizeof") as logs: