{* ../../docs_src/sub_applications/tutorial001_py39.py hl[3, 6:8] *}

### Sub-application { #sub-application }

Then, create your sub-application, and its *path operations*.

This sub-application is just another standard FastAPI application, but this is the one that will be "mounted":

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 14:16] *}

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[6:9] *}

## Добавление фоновой задачи { #add-the-background-task }

Внутри вашей функции‑обработчика пути передайте функцию задачи объекту фоновых задач методом `.add_task()`:

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[14] *}

`.add_task()` принимает следующие аргументы:

from docs_src.python_types.tutorial013_py39 import say_hello


def test_say_hello():

from docs_src.python_types.tutorial004_py39 import get_name_with_age


def test_get_name_with_age_pass_int():

from docs_src.python_types.tutorial005_py39 import get_items


def test_get_items():
    res = get_items(
        "item_a",
        "item_b",
        "item_c",
        "item_d",
        "item_e",
    )

from docs_src.python_types.tutorial007_py39 import process_items


def test_process_items():
    items_t = (1, 2, "foo")
    items_s = {b"a", b"b", b"c"}

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[6:9] *}

## Add the background task { #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_py39.py hl[14] *}

`.add_task()` receives as arguments:

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[6:9] *}

## Adicione a tarefa em segundo plano { #add-the-background-task }

Dentro da sua *função de operação de rota*, passe sua função de tarefa para o objeto de *tarefas em segundo plano* com o método `.add_task()`:

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[14] *}

O `.add_task()` recebe como argumentos:

## 纯列表请求体

如果你期望的 JSON 请求体的最外层是一个 JSON `array`（即 Python `list`），则可以在路径操作函数的参数中声明此类型，就像声明 Pydantic 模型一样：

```Python
images: List[Image]
```

例如：

{* ../../docs_src/body_nested_models/tutorial008_py39.py hl[13] *}

## 无处不在的编辑器支持

你可以随处获得编辑器支持。

即使是列表中的元素：

<img src="https://fastapi.tiangolo.com/img/tutorial/body-nested-models/image01.png">

如果你直接使用 `dict` 而不是 Pydantic 模型，那你将无法获得这种编辑器支持。

from fastapi.testclient import TestClient

from docs_src.response_cookies.tutorial001_py39 import app

client = TestClient(app)


def test_path_operation():
    response = client.post("/cookie/")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "Come to the dark side, we have cookies"}