if user_id is None:
        return {"item_id": item_id}
    else:
        return {"item_id": item_id, "user_id": user_id}


app.include_router(user_router, prefix="/users")
app.include_router(item_router, prefix="/items")

app.include_router(item_router, prefix="/users/{user_id}/items")


client = TestClient(app)


def test_get_users():
    """Check that /users returns expected data"""

/// info | Información

`users.router` contiene el `APIRouter` dentro del archivo `app/routers/users.py`.

Y `items.router` contiene el `APIRouter` dentro del archivo `app/routers/items.py`.

///

Con `app.include_router()` podemos agregar cada `APIRouter` a la aplicación principal de `FastAPI`.

Incluirá todas las rutas de ese router como parte de ella.

/// note | Detalles Técnicos

/// info | Informação

`users.router` contém o `APIRouter` dentro do arquivo `app/routers/users.py`.

E `items.router` contém o `APIRouter` dentro do arquivo `app/routers/items.py`.

///

Com `app.include_router()` podemos adicionar cada `APIRouter` ao aplicativo principal `FastAPI`.

Ele incluirá todas as rotas daquele roteador como parte dele.

/// note | Detalhes Técnicos

/// info

`users.router` contains the `APIRouter` inside of the file `app/routers/users.py`.

And `items.router` contains the `APIRouter` inside of the file `app/routers/items.py`.

///

With `app.include_router()` we can add each `APIRouter` to the main `FastAPI` application.

It will include all the routes from that router as part of it.

/// note | Technical Details

/// info | Info

`users.router` enthält den `APIRouter` in der Datei `app/routers/users.py`.

Und `items.router` enthält den `APIRouter` in der Datei `app/routers/items.py`.

///

Mit `app.include_router()` können wir jeden `APIRouter` zur Hauptanwendung `FastAPI` hinzufügen.

Es wird alle Routen von diesem Router als Teil von dieser inkludieren.

/// note | Technische Details

/// info | Примечание

`users.router` содержит `APIRouter` из файла `app/routers/users.py`.

А `items.router` содержит `APIRouter` из файла `app/routers/items.py`.

///

С помощью `app.include_router()` мы можем добавить каждый из маршрутизаторов (`APIRouter`) в основное приложение `FastAPI`.

Он подключит все маршруты заданного маршрутизатора к нашему приложению.

/// note | Технические детали

## 多次使用不同的 `prefix` 包含同一个路由器

你也可以在*同一*路由器上使用不同的前缀来多次使用 `.include_router()`。

在有些场景这可能有用，例如以不同的前缀公开同一个的 API，比方说 `/api/v1` 和 `/api/latest`。

这是一个你可能并不真正需要的高级用法，但万一你有需要了就能够用上。

## 在另一个 `APIRouter` 中包含一个 `APIRouter`

与在 `FastAPI` 应用程序中包含 `APIRouter` 的方式相同，你也可以在另一个 `APIRouter` 中包含 `APIRouter`，通过：

```Python
router.include_router(other_router)
```

            (e.g. "payment successful").
    """
    # Send the invoice, collect the money, send the notification (the callback)
    return {"msg": "Invoice received"}


app.include_router(subrouter, callbacks=events_callback_router.routes)

client = TestClient(app)


def test_get():
    response = client.post(
        "/invoices/", json={"id": "fooinvoice", "customer": "John", "total": 5.3}

@router.get("/router-decorator-depends/", dependencies=[Depends(common_parameters)])
async def router_decorator_depends():
    return {"in": "router-decorator-depends"}


app.include_router(router)

client = TestClient(app)


async def overrider_dependency_simple(q: Optional[str] = None):
    return {"q": q, "skip": 5, "limit": 10}


async def overrider_sub_dependency(k: str):