しかし同時に、`async def` で定義された関数は「awaitされる」必要があります。なので、`async def` を持つ関数は、`async def` で定義された関数内でのみ呼び出せます。

では、このニワトリと卵の問題について、最初の `async` 関数をどのように呼び出すのでしょうか？

**FastAPI**を使用している場合、その「最初の」関数が*path operation 関数*であり、FastAPIが正しく実行する方法を知っているので、心配する必要はありません。

しかし、FastAPI以外で `async` / `await` を使用したい場合は、<a href="https://docs.python.org/3/library/asyncio-task.html#coroutine" class="external-link" target="_blank">公式Pythonドキュメントを参照して下さい</a>。

Das ist keine Limitation von **FastAPI**, sondern Teil des HTTP-Protokolls.

///

## Zusammenfassung

Similar to the way you can [add `dependencies` to the *path operation decorators*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, you can add them to the `FastAPI` application.

In that case, they will be applied to all the *path operations* in the application:

//// tab | Python 3.9+

```Python hl_lines="16"
{!> ../../docs_src/dependencies/tutorial012_an_py39.py!}
```

from fastapi.testclient import TestClient

from .main import app

client = TestClient(app)


def test_read_item():
    response = client.get("/items/foo", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 200
    assert response.json() == {
        "id": "foo",
        "title": "Foo",
        "description": "There goes my hero",
    }


def test_read_item_bad_token():

# Hakkında

    page.screenshot(path="docs/en/docs/img/tutorial/sql-databases/image02.png")

    # ---------------------
    context.close()
    browser.close()


process = subprocess.Popen(
    ["fastapi", "run", "docs_src/sql_databases/tutorial002.py"],
)
try:
    for _ in range(3):
        try:
            response = httpx.get("http://localhost:8000/docs")
        except httpx.ConnectError:
            time.sleep(1)

# Body - Вложенные модели

С помощью **FastAPI**, вы можете определять, валидировать, документировать и использовать модели произвольной вложенности (благодаря библиотеке Pydantic).

## Определение полей содержащих списки

Вы можете определять атрибут как подтип. Например, тип `list` в Python:

//// tab | Python 3.10+

```Python hl_lines="12"
{!> ../../docs_src/body_nested_models/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

{!../../docs_src/body_nested_models/tutorial004.py!}
```

이는 **FastAPI**가 다음과 유사한 본문을 기대한다는 것을 의미합니다:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

다시 한번, **FastAPI**를 사용하여 해당 선언을 함으로써 얻는 것은:

* 중첩 모델도 편집기 지원(자동완성 등)

# Body - Nested Models

With **FastAPI**, you can define, validate, document, and use arbitrarily deeply nested models (thanks to Pydantic).

## List fields

You can define an attribute to be a subtype. For example, a Python `list`:

//// tab | Python 3.10+

```Python hl_lines="12"
{!> ../../docs_src/body_nested_models/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="14"

    page.screenshot(path="docs/en/docs/img/tutorial/cookie-param-models/image01.png")

    # ---------------------
    context.close()
    browser.close()


process = subprocess.Popen(
    ["fastapi", "run", "docs_src/cookie_param_models/tutorial001.py"]
)
try:
    for _ in range(3):
        try:
            response = httpx.get("http://localhost:8000/docs")
        except httpx.ConnectError: