## Eine Anwendung mit Callbacks

Sehen wir uns das alles anhand eines Beispiels an.

Stellen Sie sich vor, Sie entwickeln eine Anwendung, mit der Sie Rechnungen erstellen können.

Diese Rechnungen haben eine `id`, einen optionalen `title`, einen `customer` (Kunde) und ein `total` (Gesamtsumme).

```Python
old_dict = {
    "old key": "old value",
    "second old key": "second old value",
}
new_dict = {**old_dict, "new key": "new value"}
```

Ici, `new_dict` contiendra toutes les paires clé-valeur de `old_dict` plus la nouvelle paire clé-valeur :

```Python
{
    "old key": "old value",
    "second old key": "second old value",
    "new key": "new value",
}
```

And all these thousands of *path operations* can be as small as 3 lines:

=== "Python 3.10+"

    ```Python hl_lines="30-32"
    {!> ../../../docs_src/security/tutorial002_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="30-32"
    {!> ../../../docs_src/security/tutorial002_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="31-33"

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial005_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial005_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9-10"
    {!> ../../../docs_src/dependencies/tutorial005_an.py!}
    ```

Primero importa `Cookie`:

=== "Python 3.10+"

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

=== "Python 3.9+"

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

=== "Python 3.8+"

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

## 导入 `Field`

首先，从 Pydantic 中导入 `Field`：

=== "Python 3.10+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="19"
    {!> ../../../docs_src/dependencies/tutorial006_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="18"
    {!> ../../../docs_src/dependencies/tutorial006_an.py!}
    ```

=== "Python 3.8 Annotated가 없는 경우"

    !!! tip "팁"
        가능하다면 `Annotated`가 달린 버전을 권장합니다.

    ```Python hl_lines="17"

* `@app.delete()`
* 等等。

=== "Python 3.10+"

    ```Python hl_lines="17  22  24-27"
    {!> ../../../docs_src/response_model/tutorial001_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="17  22  24-27"
    {!> ../../../docs_src/response_model/tutorial001_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="17  22  24-27"
    {!> ../../../docs_src/response_model/tutorial001.py!}
    ```

    Например: `pip install python-multipart`.

## Импортируйте `File` и `Form`

=== "Python 3.9+"

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

=== "Python 3.6+"

    ```Python hl_lines="1"
    {!> ../../../docs_src/request_forms_and_files/tutorial001_an.py!}
    ```

=== "Python 3.6+ без Annotated"

    !!! tip "Подсказка"

=== "Python 3.10+"

    ```Python hl_lines="2"
    {!> ../../../docs_src/body/tutorial001_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body/tutorial001.py!}
    ```

## 여러분의 데이터 모델 만들기

`BaseModel`를 상속받은 클래스로 여러분의 데이터 모델을 선언합니다.

모든 어트리뷰트에 대해 표준 파이썬 타입을 사용합니다:

=== "Python 3.10+"

    ```Python hl_lines="5-9"