diff --git a/tests/gamma/csm_observability_test.py b/tests/gamma/csm_observability_test.py
index d285f8ab..26b57f7a 100644
--- a/tests/gamma/csm_observability_test.py
+++ b/tests/gamma/csm_observability_test.py
@@ -55,7 +55,8 @@ def test_csm_observability(self):
 
         with self.subTest("2_start_test_client"):
             test_client: _XdsTestClient = self.startTestClient(
-                test_server, enable_csm_observability=True,
+                test_server,
+                enable_csm_observability=True,
                 request_payload_size=271828,
                 response_payload_size=314159,
             )