//// tab | Python 3.10+

```Python hl_lines="12"
{!> ../../docs_src/body_nested_models/tutorial002_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="14"
{!> ../../docs_src/body_nested_models/tutorial002_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="14"
{!> ../../docs_src/body_nested_models/tutorial002.py!}
```

////

`q`가 선택적이지만 값이 주어질 때마다 **값이 50 글자를 초과하지 않게** 강제하려 합니다.

### `Query` 임포트

이를 위해 먼저 `fastapi`에서 `Query`를 임포트합니다:

```Python hl_lines="3"
{!../../docs_src/query_params_str_validations/tutorial002.py!}
```

## 기본값으로 `Query` 사용

이제 `Query`를 매개변수의 기본값으로 사용하여 `max_length` 매개변수를 50으로 설정합니다:

```Python hl_lines="9"
{!../../docs_src/query_params_str_validations/tutorial002.py!}
```

Dazu deklarieren wir eine Methode `__call__`:

//// tab | Python 3.9+

```Python hl_lines="12"
{!> ../../docs_src/dependencies/tutorial011_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="11"
{!> ../../docs_src/dependencies/tutorial011_an.py!}
```

////

//// tab | Python 3.8+ nicht annotiert

/// tip | "Tipp"

## 导入 `Header`

首先，导入 `Header`：

//// tab | Python 3.10+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an.py!}
```

////

## `Cookie` 임포트

먼저 `Cookie`를 임포트합니다:

//// tab | Python 3.10+

```Python hl_lines="3"
{!> ../../docs_src/cookie_params/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="3"
{!> ../../docs_src/cookie_params/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="3"
{!> ../../docs_src/cookie_params/tutorial001_an.py!}
```

////

///

## 多个模型

下面的代码展示了不同模型处理密码字段的方式，及使用位置的大致思路：

//// tab | Python 3.10+

```Python hl_lines="7  9  14  20  22  27-28  31-33  38-39"
{!> ../../docs_src/extra_models/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9  11  16  22  24  29-30  33-35  40-41"
{!> ../../docs_src/extra_models/tutorial001.py!}
```

////

### `**user_in.dict()` 简介

//// tab | Python 3.10+

```Python hl_lines="1  15"
{!> ../../docs_src/path_operation_configuration/tutorial001_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="3  17"
{!> ../../docs_src/path_operation_configuration/tutorial001_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="3  17"
{!> ../../docs_src/path_operation_configuration/tutorial001.py!}

//// tab | Python 3.10+

```Python hl_lines="1  15"
{!> ../../docs_src/path_operation_configuration/tutorial001_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="3  17"
{!> ../../docs_src/path_operation_configuration/tutorial001_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="3  17"
{!> ../../docs_src/path_operation_configuration/tutorial001.py!}

//// tab | Python 3.10+

```Python hl_lines="9"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="11"
{!> ../../docs_src/dependencies/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="12"
{!> ../../docs_src/dependencies/tutorial001_an.py!}
```

////

//// tab | Python 3.10+

```Python hl_lines="9"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="11"
{!> ../../docs_src/dependencies/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="12"
{!> ../../docs_src/dependencies/tutorial001_an.py!}
```

////