diff --git a/fastapi/openapi/utils.py b/fastapi/openapi/utils.py
index 6c4a1bd7f..ac8f76149 100644
--- a/fastapi/openapi/utils.py
+++ b/fastapi/openapi/utils.py
@@ -197,7 +197,7 @@ def get_openapi_operation_metadata(
         operation["description"] = route.description
     operation_id = route.operation_id or route.unique_id
     if len(route.methods) > 1:
-        operation_id = f'{operation_id}_{method.lower()}'
+        operation_id = f"{operation_id}_{method.lower()}"
     if operation_id in operation_ids:
         message = (
             f"Duplicate Operation ID {operation_id} for function "
diff --git a/tests/test_application.py b/tests/test_application.py
index 690258ba0..f6618ed7c 100644
--- a/tests/test_application.py
+++ b/tests/test_application.py
@@ -1171,9 +1171,9 @@ def test_openapi_schema():
                     "responses": {
                         "200": {
                             "description": "Successful Response",
-                            "content": {"application/json": {"schema": {}}}
+                            "content": {"application/json": {"schema": {}}},
                         }
-                    }
+                    },
                 },
                 "post": {
                     "summary": "Multiple Methods",
@@ -1181,15 +1181,11 @@ def test_openapi_schema():
                     "responses": {
                         "200": {
                             "description": "Successful Response",
-                            "content": {
-                                "application/json": {
-                                    "schema": {}
-                                }
-                            }
+                            "content": {"application/json": {"schema": {}}},
                         }
-                    }
-                }
-            }
+                    },
+                },
+            },
         },
         "components": {
             "schemas": {