callbacks=callback_router3.routes,
)

router2_override.include_router(router4_override)

router2_override.include_router(router4_default)

router2_default.include_router(
    router4_override,
    prefix="/level3",
    tags=["level3a", "level3b"],
    dependencies=[Depends(dep3)],
    responses={
        403: {"description": "Client error level 3"},
        503: {"description": "Server error level 3"},

    color: var(--color-text);
    /* font-size: 18px; */
    font-size: 15px;
    /* font-family: 'Fira Mono', Consolas, Menlo, Monaco, 'Courier New', Courier, monospace; */
    font-family: 'Roboto Mono', 'Fira Mono', Consolas, Menlo, Monaco, 'Courier New', Courier, monospace;
    border-radius: 4px;
    padding: 75px 45px 35px;
    position: relative;
    -webkit-box-sizing: border-box;
            box-sizing: border-box;

@router.get("/router-depends/")
async def router_depends(commons: dict = Depends(common_parameters)):
    return {"in": "router-depends", "params": commons}


@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)

from .internal import admin
from .routers import items, users

app = FastAPI(dependencies=[Depends(get_query_token)])


app.include_router(users.router)
app.include_router(items.router)
app.include_router(
    admin.router,
    prefix="/admin",
    tags=["admin"],
    dependencies=[Depends(get_token_header)],
    responses={418: {"description": "I'm a teapot"}},
)


@app.get("/")

	// Add server metrics router
	registerMetricsRouter(router)

	// Add STS router always.
	registerSTSRouter(router)

	// Add KMS router
	registerKMSRouter(router)

	// Add API router
	registerAPIRouter(router)

	router.Use(globalMiddlewares...)

	return router, nil

    )
    def post_router(item1: Item, item2: Item):
        return item1, item2  # pragma: nocover

    @sub_router.post(
        "/subrouter",
        response_model=List[Item],
        responses={404: {"model": List[Message]}},
    )
    def post_subrouter(item1: Item, item2: Item):
        return item1, item2  # pragma: nocover

    router.include_router(sub_router)

func StartHealthServer() (installReady *atomic.Value, watchReady *atomic.Value) {
	router := http.NewServeMux()
	installReady, watchReady = initRouter(router)

	go func() {
		_ = http.ListenAndServe(":"+constants.ReadinessPort, router)
	}()

	return
}

func initRouter(router *http.ServeMux) (installReady *atomic.Value, watchReady *atomic.Value) {
	installReady = &atomic.Value{}

Wir importieren das Submodul `items` direkt, anstatt nur seine Variable `router` zu importieren.

Das liegt daran, dass wir im Submodul `users` auch eine weitere Variable namens `router` haben.

Wenn wir eine nach der anderen importiert hätten, etwa:

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

from fastapi import APIRouter

router = APIRouter()


@router.get("/users/", tags=["users"])
async def read_users():
    return [{"username": "Rick"}, {"username": "Morty"}]


@router.get("/users/me", tags=["users"])
async def read_user_me():
    return {"username": "fakecurrentuser"}


@router.get("/users/{username}", tags=["users"])
async def read_user(username: str):

```Python hl_lines="35"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip
    Notice that you are not passing the router itself (`invoices_callback_router`) to `callback=`, but the attribute `.routes`, as in `invoices_callback_router.routes`.

### Check the docs