diff --git a/docs/de/docs/tutorial/background-tasks.md b/docs/de/docs/tutorial/background-tasks.md
index 05779e12c..37e636be9 100644
--- a/docs/de/docs/tutorial/background-tasks.md
+++ b/docs/de/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@ Hierzu zählen beispielsweise:
 
 Importieren Sie zunächst `BackgroundTasks` und definieren Sie einen Parameter in Ihrer *Pfadoperation-Funktion* mit der Typdeklaration `BackgroundTasks`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** erstellt für Sie das Objekt vom Typ `BackgroundTasks` und übergibt es als diesen Parameter.
 
@@ -31,13 +31,13 @@ In diesem Fall schreibt die Taskfunktion in eine Datei (den Versand einer E-Mail
 
 Und da der Schreibvorgang nicht `async` und `await` verwendet, definieren wir die Funktion mit normalem `def`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## Den Hintergrundtask hinzufügen
 
 Übergeben Sie innerhalb Ihrer *Pfadoperation-Funktion* Ihre Taskfunktion mit der Methode `.add_task()` an das *Hintergrundtasks*-Objekt:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` erhält als Argumente:
 
diff --git a/docs/em/docs/tutorial/background-tasks.md b/docs/em/docs/tutorial/background-tasks.md
index aed60c754..0b8cc52ae 100644
--- a/docs/em/docs/tutorial/background-tasks.md
+++ b/docs/em/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@
 
 🥇, 🗄 `BackgroundTasks` & 🔬 🔢 👆 *➡ 🛠️ 🔢* ⏮️ 🆎 📄 `BackgroundTasks`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** 🔜 ✍ 🎚 🆎 `BackgroundTasks` 👆 & 🚶‍♀️ ⚫️ 👈 🔢.
 
@@ -31,13 +31,13 @@
 
 & ✍ 🛠️ 🚫 ⚙️ `async` & `await`, 👥 🔬 🔢 ⏮️ 😐 `def`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## 🚮 🖥 📋
 
 🔘 👆 *➡ 🛠️ 🔢*, 🚶‍♀️ 👆 📋 🔢 *🖥 📋* 🎚 ⏮️ 👩‍🔬 `.add_task()`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` 📨 ❌:
 
@@ -51,7 +51,7 @@
 
 **FastAPI** 💭 ⚫️❔ 🔠 💼 & ❔ 🏤-⚙️ 🎏 🎚, 👈 🌐 🖥 📋 🔗 👯‍♂️ & 🏃 🖥 ⏮️:
 
-{* ../../docs_src/background_tasks/tutorial002.py hl[13,15,22,25] *}
+{* ../../docs_src/background_tasks/tutorial002.py hl[14,17,24,27] *}
 
 👉 🖼, 📧 🔜 ✍ `log.txt` 📁 *⏮️* 📨 📨.
 
diff --git a/docs/en/docs/tutorial/background-tasks.md b/docs/en/docs/tutorial/background-tasks.md
index 34685fcc4..e1fba10c8 100644
--- a/docs/en/docs/tutorial/background-tasks.md
+++ b/docs/en/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@ This includes, for example:
 
 First, import `BackgroundTasks` and define a parameter in your *path operation function* with a type declaration of `BackgroundTasks`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** will create the object of type `BackgroundTasks` for you and pass it as that parameter.
 
@@ -31,13 +31,13 @@ In this case, the task function will write to a file (simulating sending an emai
 
 And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## Add the background task
 
 Inside of your *path operation function*, pass your task function to the *background tasks* object with the method `.add_task()`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` receives as arguments:
 
diff --git a/docs/es/docs/tutorial/background-tasks.md b/docs/es/docs/tutorial/background-tasks.md
index 3fe961e41..56669b6b9 100644
--- a/docs/es/docs/tutorial/background-tasks.md
+++ b/docs/es/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@ Esto incluye, por ejemplo:
 
 Primero, importa `BackgroundTasks` y define un parámetro en tu *path operation function* con una declaración de tipo de `BackgroundTasks`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** creará el objeto de tipo `BackgroundTasks` por ti y lo pasará como ese parámetro.
 
@@ -31,13 +31,13 @@ En este caso, la función de tarea escribirá en un archivo (simulando el envío
 
 Y como la operación de escritura no usa `async` y `await`, definimos la función con un `def` normal:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## Agregar la tarea en segundo plano
 
 Dentro de tu *path operation function*, pasa tu función de tarea al objeto de *background tasks* con el método `.add_task()`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` recibe como argumentos:
 
diff --git a/docs/fr/docs/tutorial/background-tasks.md b/docs/fr/docs/tutorial/background-tasks.md
index 2065ca58e..6b3790b86 100644
--- a/docs/fr/docs/tutorial/background-tasks.md
+++ b/docs/fr/docs/tutorial/background-tasks.md
@@ -16,7 +16,7 @@ Cela comprend, par exemple :
 
 Pour commencer, importez `BackgroundTasks` et définissez un paramètre dans votre *fonction de chemin* avec `BackgroundTasks` comme type déclaré.
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** créera l'objet de type `BackgroundTasks` pour vous et le passera comme paramètre.
 
@@ -30,14 +30,14 @@ Dans cet exemple, la fonction de tâche écrira dans un fichier (afin de simuler
 
 L'opération d'écriture n'utilisant ni `async` ni `await`, on définit la fonction avec un `def` normal.
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## Ajouter une tâche d'arrière-plan
 
 Dans votre *fonction de chemin*, passez votre fonction de tâche à l'objet de type `BackgroundTasks` (`background_tasks` ici) grâce à la méthode `.add_task()` :
 
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` reçoit comme arguments :
 
@@ -51,7 +51,7 @@ Utiliser `BackgroundTasks` fonctionne aussi avec le système d'injection de dép
 
 **FastAPI** sait quoi faire dans chaque cas et comment réutiliser le même objet, afin que tous les paramètres de type `BackgroundTasks` soient fusionnés et que les tâches soient exécutées en arrière-plan :
 
-{* ../../docs_src/background_tasks/tutorial002.py hl[13,15,22,25] *}
+{* ../../docs_src/background_tasks/tutorial002.py hl[14,17,24,27] *}
 
 Dans cet exemple, les messages seront écrits dans le fichier `log.txt` après que la réponse soit envoyée.
 
diff --git a/docs/ja/docs/tutorial/background-tasks.md b/docs/ja/docs/tutorial/background-tasks.md
index 650a079fb..69429d375 100644
--- a/docs/ja/docs/tutorial/background-tasks.md
+++ b/docs/ja/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@
 
 まず初めに、`BackgroundTasks` をインポートし、` BackgroundTasks` の型宣言と共に、*path operation 関数* のパラメーターを定義します:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** は、`BackgroundTasks` 型のオブジェクトを作成し、そのパラメーターに渡します。
 
@@ -31,13 +31,13 @@
 
 また、書き込み操作では `async` と `await` を使用しないため、通常の `def` で関数を定義します。
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## バックグラウンドタスクの追加
 
 *path operations 関数* 内で、`.add_task()` メソッドを使用してタスク関数を *background tasks* オブジェクトに渡します。
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` は以下の引数を受け取ります:
 
@@ -51,7 +51,7 @@
 
 **FastAPI** は、それぞれの場合の処理​​方法と同じオブジェクトの再利用方法を知っているため、すべてのバックグラウンドタスクがマージされ、バックグラウンドで後で実行されます。
 
-{* ../../docs_src/background_tasks/tutorial002.py hl[13,15,22,25] *}
+{* ../../docs_src/background_tasks/tutorial002.py hl[14,17,24,27] *}
 
 この例では、レスポンスが送信された *後* にメッセージが `log.txt` ファイルに書き込まれます。
 
diff --git a/docs/ko/docs/tutorial/background-tasks.md b/docs/ko/docs/tutorial/background-tasks.md
index a2c4abbd9..35f04c740 100644
--- a/docs/ko/docs/tutorial/background-tasks.md
+++ b/docs/ko/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@ FastAPI에서는 응답을 반환한 후에 실행할 백그라운드 작업을
 
 먼저 아래와 같이 `BackgroundTasks`를 임포트하고, `BackgroundTasks`를 _경로 작동 함수_ 에서 매개변수로 가져오고 정의합니다.
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** 는 `BackgroundTasks` 개체를 생성하고, 매개 변수로 전달합니다.
 
@@ -31,13 +31,13 @@ FastAPI에서는 응답을 반환한 후에 실행할 백그라운드 작업을
 
 그리고 이 작업은 `async`와 `await`를 사용하지 않으므로 일반 `def` 함수로 선언합니다.
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## 백그라운드 작업 추가
 
 _경로 작동 함수_ 내에서 작업 함수를 `.add_task()` 함수 통해 _백그라운드 작업_ 개체에 전달합니다.
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` 함수는 다음과 같은 인자를 받습니다 :
 
@@ -51,7 +51,7 @@ _경로 작동 함수_ 내에서 작업 함수를 `.add_task()` 함수 통해 _
 
 **FastAPI**는 각 경우에 수행할 작업과 동일한 개체를 내부적으로 재사용하기에, 모든 백그라운드 작업이 함께 병합되고 나중에 백그라운드에서 실행됩니다.
 
-{* ../../docs_src/background_tasks/tutorial002.py hl[13,15,22,25] *}
+{* ../../docs_src/background_tasks/tutorial002.py hl[14,17,24,27] *}
 
 이 예제에서는 응답이 반환된 후에 `log.txt` 파일에 메시지가 기록됩니다.
 
diff --git a/docs/pt/docs/tutorial/background-tasks.md b/docs/pt/docs/tutorial/background-tasks.md
index 0f3796371..460619f36 100644
--- a/docs/pt/docs/tutorial/background-tasks.md
+++ b/docs/pt/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@ Isso inclui, por exemplo:
 
 Primeiro, importe `BackgroundTasks` e defina um parâmetro em sua _função de operação de caminho_ com uma declaração de tipo de `BackgroundTasks`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 O **FastAPI** criará o objeto do tipo `BackgroundTasks` para você e o passará como esse parâmetro.
 
@@ -31,13 +31,13 @@ Nesse caso, a função de tarefa gravará em um arquivo (simulando o envio de um
 
 E como a operação de gravação não usa `async` e `await`, definimos a função com `def` normal:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## Adicionar a tarefa em segundo plano
 
 Dentro de sua _função de operação de caminho_, passe sua função de tarefa para o objeto _tarefas em segundo plano_ com o método `.add_task()`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` recebe como argumentos:
 
@@ -51,7 +51,7 @@ Usar `BackgroundTasks` também funciona com o sistema de injeção de dependênc
 
 O **FastAPI** sabe o que fazer em cada caso e como reutilizar o mesmo objeto, de forma que todas as tarefas em segundo plano sejam mescladas e executadas em segundo plano posteriormente:
 
-{* ../../docs_src/background_tasks/tutorial002.py hl[13,15,22,25] *}
+{* ../../docs_src/background_tasks/tutorial002.py hl[14,17,24,27] *}
 
 Neste exemplo, as mensagens serão gravadas no arquivo `log.txt` _após_ o envio da resposta.
 
diff --git a/docs/ru/docs/tutorial/background-tasks.md b/docs/ru/docs/tutorial/background-tasks.md
index bf2e9dec3..837f2c1a8 100644
--- a/docs/ru/docs/tutorial/background-tasks.md
+++ b/docs/ru/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@
 
 Сначала импортируйте `BackgroundTasks`, потом добавьте в функцию параметр с типом `BackgroundTasks`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[3,16] *}
 
 **FastAPI** создаст объект класса `BackgroundTasks` для вас и запишет его в параметр.
 
@@ -31,13 +31,13 @@
 
 Так как операция записи не использует `async` и `await`, мы определим ее как обычную `def`:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## Добавление фоновой задачи
 
 Внутри функции вызовите метод `.add_task()` у объекта *background tasks* и передайте ему функцию, которую хотите выполнить в фоне:
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` принимает следующие аргументы:
 
diff --git a/docs/zh/docs/tutorial/background-tasks.md b/docs/zh/docs/tutorial/background-tasks.md
index 40e61add7..aba71649b 100644
--- a/docs/zh/docs/tutorial/background-tasks.md
+++ b/docs/zh/docs/tutorial/background-tasks.md
@@ -15,7 +15,7 @@
 
 首先导入 `BackgroundTasks` 并在 *路径操作函数* 中使用类型声明 `BackgroundTasks` 定义一个参数：
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[1, 13] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[2, 14] *}
 
 **FastAPI** 会创建一个 `BackgroundTasks` 类型的对象并作为该参数传入。
 
@@ -31,13 +31,13 @@
 
 由于写操作不使用 `async` 和 `await`，我们用普通的 `def` 定义函数：
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[8:11] *}
 
 ## 添加后台任务
 
 在你的 *路径操作函数* 里，用 `.add_task()` 方法将任务函数传到 *后台任务* 对象中：
 
-{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}
+{* ../../docs_src/background_tasks/tutorial001.py hl[18] *}
 
 `.add_task()` 接收以下参数：
 
@@ -59,13 +59,13 @@
 
 //// tab | Python 3.9+
 
-{* ../../docs_src/background_tasks/tutorial002_an_py39.py hl[13, 15, 22, 25] *}
+{* ../../docs_src/background_tasks/tutorial002_an_py39.py hl[14, 17, 24, 27] *}
 
 ////
 
 //// tab | Python 3.8+
 
-{* ../../docs_src/background_tasks/tutorial002_an.py hl[14, 16, 23, 26] *}
+{* ../../docs_src/background_tasks/tutorial002_an.py hl[15, 18, 25, 28] *}
 
 ////
 
diff --git a/docs_src/background_tasks/tutorial001.py b/docs_src/background_tasks/tutorial001.py
index 1720a7433..8de2485e9 100644
--- a/docs_src/background_tasks/tutorial001.py
+++ b/docs_src/background_tasks/tutorial001.py
@@ -1,15 +1,19 @@
+from typing import Dict
+
 from fastapi import BackgroundTasks, FastAPI
 
 app = FastAPI()
 
 
-def write_notification(email: str, message=""):
+def write_notification(email: str, message: str = "") -> None:
     with open("log.txt", mode="w") as email_file:
         content = f"notification for {email}: {message}"
         email_file.write(content)
 
 
 @app.post("/send-notification/{email}")
-async def send_notification(email: str, background_tasks: BackgroundTasks):
+async def send_notification(
+    email: str, background_tasks: BackgroundTasks
+) -> Dict[str, str]:
     background_tasks.add_task(write_notification, email, message="some notification")
     return {"message": "Notification sent in the background"}
diff --git a/docs_src/background_tasks/tutorial002.py b/docs_src/background_tasks/tutorial002.py
index 2e1b2f6c6..cdcead9d2 100644
--- a/docs_src/background_tasks/tutorial002.py
+++ b/docs_src/background_tasks/tutorial002.py
@@ -1,16 +1,18 @@
-from typing import Union
+from typing import Dict, Union
 
 from fastapi import BackgroundTasks, Depends, FastAPI
 
 app = FastAPI()
 
 
-def write_log(message: str):
+def write_log(message: str) -> None:
     with open("log.txt", mode="a") as log:
         log.write(message)
 
 
-def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
+def get_query(
+    background_tasks: BackgroundTasks, q: Union[str, None] = None
+) -> Union[str, None]:
     if q:
         message = f"found query: {q}\n"
         background_tasks.add_task(write_log, message)
@@ -20,7 +22,7 @@ def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
 @app.post("/send-notification/{email}")
 async def send_notification(
     email: str, background_tasks: BackgroundTasks, q: str = Depends(get_query)
-):
+) -> Dict[str, str]:
     message = f"message to {email}\n"
     background_tasks.add_task(write_log, message)
     return {"message": "Message sent"}
diff --git a/docs_src/background_tasks/tutorial002_an.py b/docs_src/background_tasks/tutorial002_an.py
index f63502b09..5485839fe 100644
--- a/docs_src/background_tasks/tutorial002_an.py
+++ b/docs_src/background_tasks/tutorial002_an.py
@@ -1,4 +1,4 @@
-from typing import Union
+from typing import Dict, Union
 
 from fastapi import BackgroundTasks, Depends, FastAPI
 from typing_extensions import Annotated
@@ -6,12 +6,14 @@ from typing_extensions import Annotated
 app = FastAPI()
 
 
-def write_log(message: str):
+def write_log(message: str) -> None:
     with open("log.txt", mode="a") as log:
         log.write(message)
 
 
-def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
+def get_query(
+    background_tasks: BackgroundTasks, q: Union[str, None] = None
+) -> Union[str, None]:
     if q:
         message = f"found query: {q}\n"
         background_tasks.add_task(write_log, message)
@@ -21,7 +23,7 @@ def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
 @app.post("/send-notification/{email}")
 async def send_notification(
     email: str, background_tasks: BackgroundTasks, q: Annotated[str, Depends(get_query)]
-):
+) -> Dict[str, str]:
     message = f"message to {email}\n"
     background_tasks.add_task(write_log, message)
     return {"message": "Message sent"}
diff --git a/docs_src/background_tasks/tutorial002_an_py310.py b/docs_src/background_tasks/tutorial002_an_py310.py
index 1fc78fbc9..c4a22ecb8 100644
--- a/docs_src/background_tasks/tutorial002_an_py310.py
+++ b/docs_src/background_tasks/tutorial002_an_py310.py
@@ -5,12 +5,12 @@ from fastapi import BackgroundTasks, Depends, FastAPI
 app = FastAPI()
 
 
-def write_log(message: str):
+def write_log(message: str) -> None:
     with open("log.txt", mode="a") as log:
         log.write(message)
 
 
-def get_query(background_tasks: BackgroundTasks, q: str | None = None):
+def get_query(background_tasks: BackgroundTasks, q: str | None = None) -> str | None:
     if q:
         message = f"found query: {q}\n"
         background_tasks.add_task(write_log, message)
@@ -20,7 +20,7 @@ def get_query(background_tasks: BackgroundTasks, q: str | None = None):
 @app.post("/send-notification/{email}")
 async def send_notification(
     email: str, background_tasks: BackgroundTasks, q: Annotated[str, Depends(get_query)]
-):
+) -> dict[str, str]:
     message = f"message to {email}\n"
     background_tasks.add_task(write_log, message)
     return {"message": "Message sent"}
diff --git a/docs_src/background_tasks/tutorial002_an_py39.py b/docs_src/background_tasks/tutorial002_an_py39.py
index bfdd14875..f7086cc8b 100644
--- a/docs_src/background_tasks/tutorial002_an_py39.py
+++ b/docs_src/background_tasks/tutorial002_an_py39.py
@@ -5,12 +5,14 @@ from fastapi import BackgroundTasks, Depends, FastAPI
 app = FastAPI()
 
 
-def write_log(message: str):
+def write_log(message: str) -> None:
     with open("log.txt", mode="a") as log:
         log.write(message)
 
 
-def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
+def get_query(
+    background_tasks: BackgroundTasks, q: Union[str, None] = None
+) -> Union[str, None]:
     if q:
         message = f"found query: {q}\n"
         background_tasks.add_task(write_log, message)
@@ -20,7 +22,7 @@ def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
 @app.post("/send-notification/{email}")
 async def send_notification(
     email: str, background_tasks: BackgroundTasks, q: Annotated[str, Depends(get_query)]
-):
+) -> dict[str, str]:
     message = f"message to {email}\n"
     background_tasks.add_task(write_log, message)
     return {"message": "Message sent"}
diff --git a/docs_src/background_tasks/tutorial002_py310.py b/docs_src/background_tasks/tutorial002_py310.py
index 626af1358..ad27a245d 100644
--- a/docs_src/background_tasks/tutorial002_py310.py
+++ b/docs_src/background_tasks/tutorial002_py310.py
@@ -3,12 +3,12 @@ from fastapi import BackgroundTasks, Depends, FastAPI
 app = FastAPI()
 
 
-def write_log(message: str):
+def write_log(message: str) -> None:
     with open("log.txt", mode="a") as log:
         log.write(message)
 
 
-def get_query(background_tasks: BackgroundTasks, q: str | None = None):
+def get_query(background_tasks: BackgroundTasks, q: str | None = None) -> str | None:
     if q:
         message = f"found query: {q}\n"
         background_tasks.add_task(write_log, message)
@@ -18,7 +18,7 @@ def get_query(background_tasks: BackgroundTasks, q: str | None = None):
 @app.post("/send-notification/{email}")
 async def send_notification(
     email: str, background_tasks: BackgroundTasks, q: str = Depends(get_query)
-):
+) -> dict[str, str]:
     message = f"message to {email}\n"
     background_tasks.add_task(write_log, message)
     return {"message": "Message sent"}