diff --git a/docs_src/custom_docs_ui/tutorial001.py b/docs_src/custom_docs_ui/tutorial001.py
index 0af2c6760..4e9b211d6 100644
--- a/docs_src/custom_docs_ui/tutorial001.py
+++ b/docs_src/custom_docs_ui/tutorial001.py
@@ -1,8 +1,8 @@
 from fastapi import FastAPI
 from fastapi.openapi.docs import (
     get_redoc_html,
-    get_swagger_ui_html,
     get_scalar_html,
+    get_swagger_ui_html,
     get_swagger_ui_oauth2_redirect_html,
 )
 
@@ -33,6 +33,7 @@ async def redoc_html():
         redoc_js_url="https://unpkg.com/redoc@next/bundles/redoc.standalone.js",
     )
 
+
 @app.get("/scalar", include_in_schema=False)
 async def scalar_html():
     return get_scalar_html(
@@ -41,6 +42,7 @@ async def scalar_html():
         scalar_js_url="https://cdn.jsdelivr.net/npm/@scalar/api-reference",
     )
 
+
 @app.get("/users/{username}")
 async def read_user(username: str):
     return {"message": f"Hello {username}"}
diff --git a/docs_src/custom_docs_ui/tutorial002.py b/docs_src/custom_docs_ui/tutorial002.py
index 94f05dd35..fe937f6b5 100644
--- a/docs_src/custom_docs_ui/tutorial002.py
+++ b/docs_src/custom_docs_ui/tutorial002.py
@@ -1,8 +1,8 @@
 from fastapi import FastAPI
 from fastapi.openapi.docs import (
     get_redoc_html,
-    get_swagger_ui_html,
     get_scalar_html,
+    get_swagger_ui_html,
     get_swagger_ui_oauth2_redirect_html,
 )
 from fastapi.staticfiles import StaticFiles
@@ -36,6 +36,7 @@ async def redoc_html():
         redoc_js_url="/static/redoc.standalone.js",
     )
 
+
 @app.get("/scalar", include_in_schema=False)
 async def scalar_html():
     return get_scalar_html(
diff --git a/fastapi/applications.py b/fastapi/applications.py
index 264fa8cb4..ac7567e20 100644
--- a/fastapi/applications.py
+++ b/fastapi/applications.py
@@ -1073,7 +1073,7 @@ class FastAPI(Starlette):
                 )
 
             self.add_route(self.redoc_url, redoc_html, include_in_schema=False)
-        
+
         if self.openapi_url and self.scalar_url:
 
             async def scalar_html(req: Request) -> HTMLResponse:
diff --git a/fastapi/openapi/docs.py b/fastapi/openapi/docs.py
index c5f1454db..38193caf3 100644
--- a/fastapi/openapi/docs.py
+++ b/fastapi/openapi/docs.py
@@ -157,6 +157,7 @@ def get_swagger_ui_html(
     """
     return HTMLResponse(html)
 
+
 def get_scalar_html(
     *,
     openapi_url: Annotated[
@@ -247,6 +248,7 @@ def get_scalar_html(
     """
     return HTMLResponse(html)
 
+
 def get_redoc_html(
     *,
     openapi_url: Annotated[
diff --git a/tests/test_application.py b/tests/test_application.py
index cbb45fb31..73cbe3a00 100644
--- a/tests/test_application.py
+++ b/tests/test_application.py
@@ -45,12 +45,14 @@ def test_redoc():
     assert response.headers["content-type"] == "text/html; charset=utf-8"
     assert "redoc@next" in response.text
 
+
 def test_scalar():
     response = client.get("/scalar")
     assert response.status_code == 200, response.text
     assert response.headers["content-type"] == "text/html; charset=utf-8"
     assert "@scalar/api-reference" in response.text
 
+
 def test_enum_status_code_response():
     response = client.get("/enum-status-code")
     assert response.status_code == 201, response.text
diff --git a/tests/test_tutorial/test_custom_docs_ui/test_tutorial001.py b/tests/test_tutorial/test_custom_docs_ui/test_tutorial001.py
index 6242a6efc..b0043f8ac 100644
--- a/tests/test_tutorial/test_custom_docs_ui/test_tutorial001.py
+++ b/tests/test_tutorial/test_custom_docs_ui/test_tutorial001.py
@@ -37,11 +37,13 @@ def test_redoc_html(client: TestClient):
     assert response.status_code == 200, response.text
     assert "https://unpkg.com/redoc@next/bundles/redoc.standalone.js" in response.text
 
+
 def test_scalar_html(client: TestClient):
     response = client.get("/scalar")
     assert response.status_code == 200, response.text
     assert "https://cdn.jsdelivr.net/npm/@scalar/api-reference" in response.text
 
+
 def test_api(client: TestClient):
     response = client.get("/users/john")
     assert response.status_code == 200, response.text
diff --git a/tests/test_tutorial/test_custom_docs_ui/test_tutorial002.py b/tests/test_tutorial/test_custom_docs_ui/test_tutorial002.py
index 90ea1004a..2d5bf8628 100644
--- a/tests/test_tutorial/test_custom_docs_ui/test_tutorial002.py
+++ b/tests/test_tutorial/test_custom_docs_ui/test_tutorial002.py
@@ -35,6 +35,7 @@ def test_redoc_html(client: TestClient):
     assert response.status_code == 200, response.text
     assert "/static/redoc.standalone.js" in response.text
 
+
 def test_scalar_html(client: TestClient):
     response = client.get("/scalar")
     assert response.status_code == 200, response.text