For example, `dependency_c` can have a dependency on `dependency_b`, and `dependency_b` on `dependency_a`:

{* ../../docs_src/dependencies/tutorial008_an_py39.py hl[6,14,22] *}

And all of them can use `yield`.

In this case `dependency_c`, to execute its exit code, needs the value from `dependency_b` (here named `dep_b`) to still be available.

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

Or in Python 3.10 and above:

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

For example:

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


/// info

`Body` also has all the same extra validation and metadata parameters as `Query`, `Path` and others you will see later.

///

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

Oder in Python 3.10 und darüber:

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

Zum Beispiel:

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

/// info | Info

`Body` hat die gleichen zusätzlichen Validierungs- und Metadaten-Parameter wie `Query`, `Path` und andere, die Sie später kennenlernen werden.

///

```Python
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.

///

Pydantic의 모델 구성을 사용하여 추가(`extra`) 필드를 금지(`forbid`)할 수 있습니다:

{* ../../docs_src/cookie_param_models/tutorial002_an_py39.py hl[10] *}

클라이언트가 **추가 쿠키**를 보내려고 시도하면, **오류** 응답을 받게 됩니다.

<abbr title="이건 또 다른 농담입니다. 제 말에 귀 기울이지 마세요. 커피랑 쿠키 좀 드세요. ☕">API가 거부</abbr>하는데도 동의를 얻기 위해 애쓰는 불쌍한 쿠키 배너(팝업)들. 🍪

Pydanticのモデルの Configuration を利用して、 `extra` フィールドを `forbid` とすることができます。

{* ../../docs_src/cookie_param_models/tutorial002_an_py39.py hl[10] *}

もしクライアントが**余分なクッキー**を送ろうとすると、**エラー**レスポンスが返されます。

{* ../../docs_src/pydantic_v1_in_v2/tutorial004_an_py310.py hl[4,18] *}

### In Schritten migrieren { #migrate-in-steps }

/// tip | Tipp

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

Ou como em Python 3.10 e versões superiores:

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

Por exemplo:

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

/// info | Informação

`Body` também possui todas as validações adicionais e metadados de parâmetros como em `Query`,`Path` e outras que você verá depois.

///

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

Ou bien, en Python 3.10 et supérieur :

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

Par exemple :

{* ../../docs_src/body_multiple_params/tutorial004_an_py310.py hl[27] *}

/// info

`Body` possède les mêmes paramètres de validation additionnels et de gestion des métadonnées que `Query` et `Path`, ainsi que d'autres que nous verrons plus tard.

///

# Get Current User { #get-current-user }

In the previous chapter the security system (which is based on the dependency injection system) was giving the *path operation function* a `token` as a `str`:

{* ../../docs_src/security/tutorial001_an_py39.py hl[12] *}

But that is still not that useful.

Let's make it give us the current user.

## Create a user model { #create-a-user-model }

First, let's create a Pydantic user model.