diff --git a/src/python_testing/TC_DEM_2_10.py b/src/python_testing/TC_DEM_2_10.py
index 8fe05769b4243e..81e1ca83cb18a8 100644
--- a/src/python_testing/TC_DEM_2_10.py
+++ b/src/python_testing/TC_DEM_2_10.py
@@ -155,5 +155,6 @@ async def test_TC_DEM_2_10(self):
         self.step("10")
         await self.send_test_event_trigger_forecast_adjustment_clear()
 
+
 if __name__ == "__main__":
     default_matter_test_main()
diff --git a/src/python_testing/matter_testing_support.py b/src/python_testing/matter_testing_support.py
index 3a7edc093b0edb..e4bbdac56ddf92 100644
--- a/src/python_testing/matter_testing_support.py
+++ b/src/python_testing/matter_testing_support.py
@@ -410,7 +410,7 @@ def reset(self):
             self._attribute_reports[a] = []
         self._q = queue.Queue()
 
-    async def start(self, dev_ctrl, node_id: int, endpoint: int, fabric_filtered: bool = False, min_interval_sec: int = 0, max_interval_sec: int = 5, keepSubscriptions: bool=True) -> Any:
+    async def start(self, dev_ctrl, node_id: int, endpoint: int, fabric_filtered: bool = False, min_interval_sec: int = 0, max_interval_sec: int = 5, keepSubscriptions: bool = True) -> Any:
         """This starts a subscription for attributes on the specified node_id and endpoint. The cluster is specified when the class instance is created."""
         self._subscription = await dev_ctrl.ReadAttribute(
             nodeid=node_id,