diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index f0cc04a40..f54bbb379 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -1011,7 +1011,9 @@ class IdMaker:
                         new_id = f"{id}{suffix}{id_suffixes[id]}"
                     resolved_ids[index] = new_id
                     id_suffixes[id] += 1
-        assert len(resolved_ids) == len(set(resolved_ids)), f"Internal error: {resolved_ids=}"
+        assert len(resolved_ids) == len(
+            set(resolved_ids)
+        ), f"Internal error: {resolved_ids=}"
         return resolved_ids
 
     def _resolve_ids(self) -> Iterable[str]: