diff --git a/docs_src/query_params_str_validations/tutorial015_an_py310.py b/docs_src/query_params_str_validations/tutorial015_an_py310.py
index 6097cafa0..05aadd714 100644
--- a/docs_src/query_params_str_validations/tutorial015_an_py310.py
+++ b/docs_src/query_params_str_validations/tutorial015_an_py310.py
@@ -26,7 +26,9 @@ async def read_items(
     if id:
         item = data.get(id)
         if item is None:
-            raise HTTPException(status_code=404, detail=f"Item with id '{id}' not found")
+            raise HTTPException(
+                status_code=404, detail=f"Item with id '{id}' not found"
+            )
     else:
         id, item = random.choice(list(data.items()))
     return {"id": id, "name": item}