q: Union[str, None] = None
```

Или в Python 3.10 и выше:

```Python
q: str | None = None
```

Например:

{* ../../docs_src/body_multiple_params/tutorial004_an_py310.py hl[28] *}

/// info | Информация

`Body` также имеет все те же дополнительные параметры валидации и метаданных, как у `Query`,`Path` и других, которые вы увидите позже.

///

///

O parâmetro `status_code` recebe um número com o código de status HTTP.

/// info | Informação

`status_code` também pode receber um `IntEnum`, como o do Python <a href="https://docs.python.org/3/library/http.html#http.HTTPStatus" class="external-link" target="_blank">`http.HTTPStatus`</a>.

///

	for g := range strings.SplitSeq(string(buf), "\n\n") {
		// Again split on a new line, the first line of the second half contains the info about the go routine.
		sl := strings.SplitN(g, "\n", 2)
		if len(sl) != 2 {
			continue
		}
		stack := strings.TrimSpace(sl[1])
		// ignore the testing go routine.

///

El parámetro `status_code` recibe un número con el código de estado HTTP.

/// info | Información

`status_code` también puede recibir un `IntEnum`, como por ejemplo el <a href="https://docs.python.org/3/library/http.html#http.HTTPStatus" class="external-link" target="_blank">`http.HTTPStatus`</a> de Python.

///

def test_openapi_schema():
    with client:
        response = client.get("/openapi.json")
        assert response.json() == {
            "openapi": "3.1.0",
            "info": {"title": "FastAPI", "version": "0.1.0"},
            "paths": {
                "/invoices/": {
                    "post": {
                        "summary": "Create Invoice",

这些安全方案在使用 OAuth2 时，还可以声明和使用作用域。

**作用域**只是（不带空格的）字符串。

常用于声明特定安全权限，例如：

* 常见用例为，`users:read` 或 `users:write`
* 脸书和 Instagram 使用 `instagram_basic`
* 谷歌使用 `https://www.googleapis.com/auth/drive`

/// info | 说明

OAuth2 中，**作用域**只是声明特定权限的字符串。

是否使用冒号 `:` 等符号，或是不是 URL 并不重要。

这些细节只是特定的实现方式。

对 OAuth2 来说，它们都只是字符串而已。

///

## 全局纵览

To achieve that, first import:

* `Query` from `fastapi`
* `Annotated` from `typing`

{* ../../docs_src/query_params_str_validations/tutorial002_an_py310.py hl[1,3] *}

/// info

FastAPI added support for `Annotated` (and started recommending it) in version 0.95.0.

If you have an older version, you would get errors when trying to use `Annotated`.

## Return the same input data { #return-the-same-input-data }

Here we are declaring a `UserIn` model, it will contain a plaintext password:

{* ../../docs_src/response_model/tutorial002_py310.py hl[7,9] *}

/// info

To use `EmailStr`, first install <a href="https://github.com/JoshData/python-email-validator" class="external-link" target="_blank">`email-validator`</a>.

### Executar o App { #run-the-app }

Você pode executar o app:

<div class="termy">

```console
$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

Sie und Ihr Schwarm essen die Burger und haben eine schöne Zeit. ✨

<img src="/img/async/concurrent-burgers/concurrent-burgers-07.png" class="illustration">

/// info | Info

Die wunderschönen Illustrationen stammen von <a href="https://www.instagram.com/ketrinadrawsalot" class="external-link" target="_blank">Ketrina Thompson</a>. 🎨

///

---