# Classes como Dependências

Antes de nos aprofundarmos no sistema de **Injeção de Dependência**, vamos melhorar o exemplo anterior.

## `dict` do exemplo anterior

No exemplo anterior, nós retornávamos um `dict` da nossa dependência ("injetável"):

//// tab | Python 3.10+

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

////

//// tab | Python 3.9+

```Python hl_lines="11"

```python hl_lines="16-17  24-25"
{!> ../../docs_src/dependencies/tutorial008.py!}
```

////

Da mesma forma, você pode ter algumas dependências com `yield` e outras com `return` e ter uma relação de dependência entre algumas dos dois tipos.

E você poderia ter uma única dependência que precisa de diversas outras dependências com `yield`, etc.

Você pode ter qualquer combinação de dependências que você quiser.

```

////

//// tab | Python 3.8+

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

////

//// tab | Python 3.10+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python hl_lines="7"
{!> ../../docs_src/dependencies/tutorial001_py310.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+ nicht annotiert

```Python hl_lines="2-4"
{!../../docs_src/dependencies/tutorial007.py!}
```

The yielded value is what is injected into *path operations* and other dependencies:

```Python hl_lines="4"
{!../../docs_src/dependencies/tutorial007.py!}
```

The code following the `yield` statement is executed after the response has been delivered:

```Python hl_lines="5-6"
{!../../docs_src/dependencies/tutorial007.py!}
```

/// tip

例如，你可以使用这种方式创建一个数据库会话，并在完成后关闭它。

在发送响应之前，只会执行 `yield` 语句及之前的代码：

```Python hl_lines="2-4"
{!../../docs_src/dependencies/tutorial007.py!}
```

生成的值会注入到 *路由函数* 和其他依赖项中：

```Python hl_lines="4"
{!../../docs_src/dependencies/tutorial007.py!}
```

`yield` 语句后面的代码会在创建响应后，发送响应前执行：

```Python hl_lines="5-6"
{!../../docs_src/dependencies/tutorial007.py!}
```

/// tip | 提示

你可以使用 `async` 或普通函数。

レスポンスを送信する前に`yield`文を含む前のコードのみが実行されます。

```Python hl_lines="2 3 4"
{!../../docs_src/dependencies/tutorial007.py!}
```

生成された値は、*path operations*や他の依存関係に注入されるものです:

```Python hl_lines="4"
{!../../docs_src/dependencies/tutorial007.py!}
```

`yield`文に続くコードは、レスポンスが送信された後に実行されます:

```Python hl_lines="5 6"
{!../../docs_src/dependencies/tutorial007.py!}
```

/// tip | "豆知識"

`async`や通常の関数を使用することができます。

//// 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 3.6+

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

////

//// tab | Python 3.10+ без Annotated

```Python hl_lines="2-4"
{!../../docs_src/dependencies/tutorial007.py!}
```

Der ge`yield`ete Wert ist das, was in *Pfadoperationen* und andere Abhängigkeiten eingefügt wird:

```Python hl_lines="4"
{!../../docs_src/dependencies/tutorial007.py!}
```

Der auf die `yield`-Anweisung folgende Code wird ausgeführt, nachdem die Response gesendet wurde:

```Python hl_lines="2-4"
{!../../docs_src/dependencies/tutorial007.py!}
```

Полученное значение и есть то, что будет внедрено в функцию операции пути и другие зависимости:

```Python hl_lines="4"
{!../../docs_src/dependencies/tutorial007.py!}
```

Код, следующий за оператором `yield`, выполняется после доставки ответа:

```Python hl_lines="5-6"
{!../../docs_src/dependencies/tutorial007.py!}
```

/// tip | "Подсказка"