def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Ya da <code>async def</code>...</summary>

Eğer kodunuzda `async` / `await` varsa, `async def` kullanalım:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Або використайте <code>async def</code>...</summary>

Якщо ваш код використовує `async` / `await`, скористайтеся `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Ou utilisez <code>async def</code> ...</summary>

Si votre code utilise `async` / `await`, utilisez `async def` :

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>⚖️ ⚙️ <code>async def</code>...</summary>

🚥 👆 📟 ⚙️ `async` / `await`, ⚙️ `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>또는 <code>async def</code> 사용하기...</summary>

여러분의 코드가 `async` / `await`을 사용한다면, `async def`를 사용하십시오.

```Python hl_lines="9 14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>或可以使用 <code>async def</code>...</summary>

如果你的程式使用 `async` / `await`，請使用 `async def`：

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

上述这些操作都是可行的，**FastAPI** 知道该怎么处理。

!!! note "笔记"

    如里不了解异步，请参阅[异步：*“着急了？”*](../../async.md){.internal-link target=_blank} 一章中 `async` 和 `await` 的内容。

## 与 OpenAPI 集成

依赖项及子依赖项的所有请求声明、验证和需求都可以集成至同一个 OpenAPI 概图。

所以，交互文档里也会显示依赖项的所有信息：

<img src="/img/tutorial/dependencies/image01.png">

## 简单用法

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Albo użyj <code>async def</code>...</summary>

Jeżeli twój kod korzysta z `async` / `await`, użyj `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Или используйте <code>async def</code>...</summary>

Если ваш код использует `async` / `await`, используйте `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

def read_item(item_id: int, q: str = Optional[None]):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Oppure usa <code>async def</code>...</summary>

Se il tuo codice usa `async` / `await`, allora usa `async def`:

```Python hl_lines="7  12"
from fastapi import FastAPI
from typing import Optional

app = FastAPI()


@app.get("/")
async def read_root():