diff --git a/fastapi/routing.py b/fastapi/routing.py
index 9d6759ba4..f7281f20b 100644
--- a/fastapi/routing.py
+++ b/fastapi/routing.py
@@ -401,21 +401,25 @@ def get_request_handler(
 
                     # Create a new BackgroundTasks to hold both
                     combined_tasks = BackgroundTasks()
-                    
+
                     # Add existing response tasks
                     if isinstance(raw_response.background, BackgroundTasks):
                         combined_tasks.tasks.extend(raw_response.background.tasks)
                     elif isinstance(raw_response.background, BackgroundTask):
                         combined_tasks.tasks.append(raw_response.background)
-                    
+
                     # Add dependency tasks
                     # solved_result.background_tasks is always BackgroundTasks (from dependencies/utils.py)
                     if isinstance(solved_result.background_tasks, BackgroundTasks):
-                        combined_tasks.tasks.extend(solved_result.background_tasks.tasks)
-                    elif isinstance(solved_result.background_tasks, BackgroundTask):  # pragma: no cover
-                         # Should not happen for BackgroundTasks dependency but safe to handle
+                        combined_tasks.tasks.extend(
+                            solved_result.background_tasks.tasks
+                        )
+                    elif isinstance(
+                        solved_result.background_tasks, BackgroundTask
+                    ):  # pragma: no cover
+                        # Should not happen for BackgroundTasks dependency but safe to handle
                         combined_tasks.tasks.append(solved_result.background_tasks)
-                        
+
                     raw_response.background = combined_tasks
                 response = raw_response
             else:
diff --git a/tests/test_issue_11215.py b/tests/test_issue_11215.py
index ce690a47f..00e4cfa82 100644
--- a/tests/test_issue_11215.py
+++ b/tests/test_issue_11215.py
@@ -4,6 +4,7 @@ from starlette.responses import BackgroundTask, Response
 
 app = FastAPI()
 
+
 @app.get("/")
 def endpoint(tasks: BackgroundTasks):
     tasks.add_task(lambda: print("Dependency task executed"))
@@ -12,8 +13,10 @@ def endpoint(tasks: BackgroundTasks):
         background=BackgroundTask(lambda: print("Response task executed")),
     )
 
+
 client = TestClient(app)
 
+
 def test_issue_11215(capsys):
     client.get("/")
     captured = capsys.readouterr()
diff --git a/tests/test_issue_11215_coverage.py b/tests/test_issue_11215_coverage.py
index a1134aecf..1eaa96fc5 100644
--- a/tests/test_issue_11215_coverage.py
+++ b/tests/test_issue_11215_coverage.py
@@ -5,20 +5,23 @@ from starlette.responses import Response
 
 app = FastAPI()
 
+
 @app.get("/")
 def endpoint(tasks: BackgroundTasks):
     tasks.add_task(lambda: print("Dependency task"))
-    
+
     response_tasks = StarletteBackgroundTasks()
     response_tasks.add_task(lambda: print("Response task"))
-    
+
     return Response(
         content="Custom response",
         background=response_tasks,
     )
 
+
 client = TestClient(app)
 
+
 def test_issue_11215_response_background_tasks_collection(capsys):
     client.get("/")
     captured = capsys.readouterr()