We are importing the submodule `items` directly, instead of importing just its variable `router`.

This is because we also have another variable named `router` in the submodule `users`.

If we had imported one after the other, like:

```Python
from .routers.items import router
from .routers.users import router
```

### 避免名称冲突

我们将直接导入 `items` 子模块，而不是仅导入其 `router` 变量。

这是因为我们在 `users` 子模块中也有另一个名为 `router` 的变量。

如果我们一个接一个地导入，例如：

```Python
from .routers.items import router
from .routers.users import router
```

来自 `users` 的 `router` 将覆盖来自 `items` 中的 `router`，我们将无法同时使用它们。

因此，为了能够在同一个文件中使用它们，我们直接导入子模块：

```Python hl_lines="5" title="app/main.py"

{!../../../docs_src/custom_request_and_route/tutorial002.py!}
```

## Custom `APIRoute` class in a router

You can also set the `route_class` parameter of an `APIRouter`:

```Python hl_lines="26"
{!../../../docs_src/custom_request_and_route/tutorial003.py!}
```

```Python hl_lines="26-27  30"
{!../../../docs_src/dependency_testing/tutorial001.py!}
```

!!! tip "提示"

    **FastAPI** 应用中的任何位置都可以实现覆盖依赖项。

    原依赖项可用于*路径操作函数*、*路径操作装饰器*（不需要返回值时）、`.include_router()` 调用等。

    FastAPI 可以覆盖这些位置的依赖项。

然后，使用 `app.dependency_overrides` 把覆盖依赖项重置为空**字典**：

```Python
app.dependency_overrides = {}
```

!!! tip "提示"

```Python hl_lines="28-29  32"
{!../../../docs_src/dependency_testing/tutorial001.py!}
```

!!! tip
    👆 💪 ⚒ 🔗 🔐 🔗 ⚙️ 🙆 👆 **FastAPI** 🈸.

    ⏮️ 🔗 💪 ⚙️ *➡ 🛠️ 🔢*, *➡ 🛠️ 👨‍🎨* (🕐❔ 👆 🚫 ⚙️ 📨 💲), `.include_router()` 🤙, ♒️.

    FastAPI 🔜 💪 🔐 ⚫️.

⤴️ 👆 💪 ⏲ 👆 🔐 (❎ 👫) ⚒ `app.dependency_overrides` 🛁 `dict`:

```Python
app.dependency_overrides = {}
```

!!! tip

```

## 🛃 `APIRoute` 🎓 📻

👆 💪 ⚒ `route_class` 🔢 `APIRouter`:

```Python hl_lines="26"
{!../../../docs_src/custom_request_and_route/tutorial003.py!}
```

👉 🖼, *➡ 🛠️* 🔽 `router` 🔜 ⚙️ 🛃 `TimedRoute` 🎓, & 🔜 ✔️ ➕ `X-Response-Time` 🎚 📨 ⏮️ 🕰 ⚫️ ✊ 🏗 📨:

```Python hl_lines="13-20"
{!../../../docs_src/custom_request_and_route/tutorial003.py!}

That means that, for example, to apply authentication to all the *path operations* in a router it would end up being done in a different file, instead of keeping related logic together.

                    // `outerClassId`.
                    if (receiverExpression == expression) {
                        // If there is still an outer class, then return symbol of that class
                        outerClassId?.let { return listOfNotNull(it.toTargetPsi(session, symbolBuilder)) }
                        // Otherwise, it should be a package, so we return that

$color-stop: 50%, $end-color: $red) {\n  background-image: linear-gradient($start-color, $mid-color $color-stop, $end-color);\n  background-repeat: no-repeat;\n}\n@mixin gradient-radial($inner-color: $gray-700, $outer-color: $gray-800) {\n  background-image: radial-gradient(circle, $inner-color, $outer-color);\n  background-repeat: no-repeat;\n}\n@mixin gradient-striped($color: rgba($white, .15), $angle: 45deg) {\n  background-image: linear-gradient($angle, $color 25%, transparent 25%, transparent 50%, $color...

        builder.body("") // We forbid bodies for 204 and 205.
      }
    }
    server.enqueue(builder.build())
    if (responseCode == HttpURLConnection.HTTP_CLIENT_TIMEOUT) {
      // 408's are a bit of an outlier because we may repeat the request if we encounter this
      // response code. In this scenario, there are 2 responses: the initial 408 and then the 200