CA:FALSE
    Signature Algorithm: ED25519
         7e:aa:be:ed:47:4d:b9:2f:fc:ed:7f:5a:fc:6b:c0:05:5b:f5:
         a0:31:fe:86:e3:8e:3f:49:af:6d:d5:ac:c7:c4:57:47:ce:97:
         7d:ab:b8:e9:75:ec:b4:39:fb:c8:cf:53:16:5b:1f:15:b6:7f:
         5a:d1:35:2d:fc:31:3a:10:e7:0c
```

> Observe the `Subject: CN = consoleAdmin` field.

//// tab | Python 3.10+

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

////

//// tab | Python 3.9+

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

////

Мы «обернём» это в `Annotated`, и получится:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.9+

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

////

Обидві операції шляху вимагають заголовок `X-Token`.

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/app_testing/app_b_an_py39/main.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/app_testing/app_b_an/main.py!}
```

////

**FastAPI** 知道在每种情况下该做什么以及如何复用同一对象，因此所有后台任务被合并在一起并且随后在后台运行：

//// tab | Python 3.10+

{* ../../docs_src/background_tasks/tutorial002_an_py310.py hl[13, 15, 22, 25] *}

////

//// tab | Python 3.9+

{* ../../docs_src/background_tasks/tutorial002_an_py39.py hl[13, 15, 22, 25] *}

////

//// tab | Python 3.8+

{* ../../docs_src/background_tasks/tutorial002_an.py hl[14, 16, 23, 26] *}

////

///

## 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：

{* ../../docs_src/extra_models/tutorial001_py310.py hl[7,9,14,20,22,27:28,31:33,38:39] *}

### `**user_in.dict()` 简介

#### Pydantic 的 `.dict()`

`user_in` 是类 `UserIn` 的 Pydantic 模型。

Pydantic 模型支持 `.dict()` 方法，能返回包含模型数据的**字典**。

因此，如果使用如下方式创建 Pydantic 对象 `user_in`：

```Python

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

////

//// tab | Python 3.9+

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

////

Was wir tun werden, ist, dies mit `Annotated` zu wrappen, sodass es zu:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.9+

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

////

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

////

//// tab | Python 3.9+

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

////

O que faremos é envolver isso com `Annotated`, para que fique assim:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.9+

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

////

有个 `POST` 操作会返回一些错误。

所有*路径操作* 都需要一个`X-Token` 头。

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/app_testing/app_b_an_py39/main.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/app_testing/app_b_an/main.py!}
```

////

/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.

The `str | None` (Python 3.10+) or `Union` in `Union[str, None]` (Python 3.9+) is not used by FastAPI to determine that the value is not required, it will know it's not required because it has a default value of `= None`.

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

////

//// tab | Python 3.9+

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

////

What we will do is wrap that with `Annotated`, so it becomes:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.9+

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

////