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"""

## 🔌 🎏 📻 💗 🕰 ⏮️ 🎏 `prefix`

👆 💪 ⚙️ `.include_router()` 💗 🕰 ⏮️ *🎏* 📻 ⚙️ 🎏 🔡.

👉 💪 ⚠, 🖼, 🎦 🎏 🛠️ 🔽 🎏 🔡, ✅ `/api/v1` & `/api/latest`.

👉 🏧 ⚙️ 👈 👆 5️⃣📆 🚫 🤙 💪, ✋️ ⚫️ 📤 💼 👆.

## 🔌 `APIRouter` ➕1️⃣

🎏 🌌 👆 💪 🔌 `APIRouter` `FastAPI` 🈸, 👆 💪 🔌 `APIRouter` ➕1️⃣ `APIRouter` ⚙️:

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

```

/// 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

`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 | "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 | "Detalhe Técnico"

    app = FastAPI()

    router = APIRouter(prefix="/nested")

    @router.get("/test")
    async def test(var: Annotated[str, Query()] = "bar"):
        return {"foo": var}

    app.include_router(router)

    client = TestClient(app)

    response = client.get("/nested/test")
    assert response.status_code == 200
    assert response.json() == {"foo": "bar"}


def test_openapi_schema():

            (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}

## 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)
```

@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):