```Python hl_lines="7"
{!../../../docs_src/query_params_str_validations/tutorial006b.py!}
```

!!! info
    🚥 👆 🚫 👀 👈 `...` ⏭: ⚫️ 🎁 👁 💲, ⚫️ <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">🍕 🐍 &amp; 🤙 "❕"</a>.

    ⚫️ ⚙️ Pydantic &amp; FastAPI 🎯 📣 👈 💲 ✔.

👉 🔜 ➡️ **FastAPI** 💭 👈 👉 🔢 ✔.

### ✔ ⏮️ `None`

```Python hl_lines="7"
{!../../../docs_src/query_params_str_validations/tutorial006b.py!}
```

!!! info
    如果你之前没见过 `...` 这种用法：它是一个特殊的单独值，它是 <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">Python 的一部分并且被称为「省略号」</a>。
    Pydantic 和 FastAPI 使用它来显式的声明需要一个值。

这将使 **FastAPI** 知道此查询参数是必需的。

### 使用`None`声明必需参数

Ensuite, quand c'est votre tour, vous faites des actions "productives" 🤓, vous étudiez le menu, décidez ce que vous voulez, demandez à votre crush 😍 son choix, payez 💸, vérifiez que vous utilisez la bonne carte de crédit, vérifiez que le montant débité sur la carte est correct, vérifiez que la commande contient les bons produits, etc.

    ```

!!! info "Дополнительная информация"
    Если вы ранее не сталкивались с `...`: это специальное значение, <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">часть языка Python и называется "Ellipsis"</a>.

    Используется в Pydantic и FastAPI для определения, что значение требуется обязательно.

    ```

!!! info
    Falls Sie das `...` bisher noch nicht gesehen haben: Es ist ein spezieller einzelner Wert, <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">Teil von Python und wird „Ellipsis“ genannt</a> (Deutsch: Ellipse).

    Es wird von Pydantic und FastAPI verwendet, um explizit zu deklarieren, dass ein Wert erforderlich ist.

    * This fixes an error in Uvicorn that otherwise would be thrown: `RuntimeError: Response content longer than Content-Length`.
    * This removes `fastapi.openapi.constants.STATUS_CODES_WITH_NO_BODY`, it is replaced by a function in utils.

### Translations

    {!> ../../../docs_src/query_params_str_validations/tutorial006b.py!}
    ```

!!! info
    If you hadn't seen that `...` before: it is a special single value, it is <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">part of Python and is called "Ellipsis"</a>.

    It is used by Pydantic and FastAPI to explicitly declare that a value is required.

    link: https://dev.to/teresafds/authorization-on-fastapi-with-casbin-41og
    title: Authorization on FastAPI with Casbin
  - author: New Relic
    author_link: https://newrelic.com
    link: https://newrelic.com/instant-observability/fastapi/e559ec64-f765-4470-a15f-1901fcebb468
    title: How to monitor FastAPI application performance using Python agent
  - author: Jean-Baptiste Rocher
    author_link: https://hashnode.com/@jibrocher

# Status Codes

You can import the `status` module from `fastapi`:

```python
from fastapi import status
```

`status` is provided directly by Starlette.

It contains a group of named constants (variables) with integer status codes.

For example:

* 200: `status.HTTP_200_OK`
* 403: `status.HTTP_403_FORBIDDEN`
* etc.

from fastapi.dependencies.models import Dependant
from fastapi.dependencies.utils import get_flat_dependant, get_flat_params
from fastapi.encoders import jsonable_encoder
from fastapi.openapi.constants import METHODS_WITH_BODY, REF_PREFIX, REF_TEMPLATE
from fastapi.openapi.models import OpenAPI
from fastapi.params import Body, Param
from fastapi.responses import Response
from fastapi.types import ModelNameMap