diff --git a/tests/test_sentinel.py b/tests/test_sentinel.py
index b1e53e7f82..c3e898e129 100644
--- a/tests/test_sentinel.py
+++ b/tests/test_sentinel.py
@@ -243,7 +243,12 @@ def test_openapi_schema():
                 "Item": {
                     "title": "Item",
                     "type": "object",
-                    "properties": {"data": {"title": "Data", "anyOf": [{"type": "string"}, {"type": "null"}]}},
+                    "properties": {
+                        "data": {
+                            "title": "Data",
+                            "anyOf": [{"type": "string"}, {"type": "null"}],
+                        }
+                    },
                 },
                 "ValidationError": {
                     "title": "ValidationError",