func registerAPIRouter(router *mux.Router) {
	// Initialize API.
	api := objectAPIHandlers{
		ObjectAPI: newObjectLayerFn,
	}

	// API Router
	apiRouter := router.PathPrefix(SlashSeparator).Subrouter()

	var routers []*mux.Router
	for _, domainName := range globalDomainNames {
		if IsKubernetes() {

const (
	prometheusJWT    prometheusAuthType = "jwt"
	prometheusPublic prometheusAuthType = "public"
)

// registerMetricsRouter - add handler functions for metrics.
func registerMetricsRouter(router *mux.Router) {
	// metrics router
	metricsRouter := router.NewRoute().PathPrefix(minioReservedBucketPath).Subrouter()
	authType := prometheusAuthType(strings.ToLower(env.Get(EnvPrometheusAuthType, string(prometheusJWT))))

	auth := AuthMiddleware

type adminAPIHandlers struct{}

// registerAdminRouter - Add handler functions for each service REST API routes.
func registerAdminRouter(router *mux.Router, enableConfigOps bool) {
	adminAPI := adminAPIHandlers{}
	// Admin router
	adminRouter := router.PathPrefix(adminPathPrefix).Subrouter()

	adminVersions := []string{
		adminAPIVersionPrefix,
	}

	// 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

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
```

///

### ❎ 📛 💥

👥 🏭 🔁 `items` 🔗, ↩️ 🏭 🚮 🔢 `router`.

👉 ↩️ 👥 ✔️ ➕1️⃣ 🔢 📛 `router` 🔁 `users`.

🚥 👥 ✔️ 🗄 1️⃣ ⏮️ 🎏, 💖:

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

`router` ⚪️➡️ `users` 🔜 📁 1️⃣ ⚪️➡️ `items` & 👥 🚫🔜 💪 ⚙️ 👫 🎏 🕰.

, 💪 ⚙️ 👯‍♂️ 👫 🎏 📁, 👥 🗄 🔁 🔗:

    sub_router = APIRouter(lifespan=subrouter_lifespan)

    router = APIRouter(lifespan=router_lifespan)
    router.include_router(sub_router)

    app = FastAPI(lifespan=lifespan)
    app.include_router(router)

    @app.get("/")
    def main(request: Request) -> Dict[str, str]:
        assert request.state.app
        assert request.state.router
        assert request.state.sub_router

        if responses is None:
            responses = {}
        for route in router.routes:
            if isinstance(route, APIRoute):
                combined_responses = {**responses, **route.responses}
                use_response_class = get_value_or_default(
                    route.response_class,
                    router.default_response_class,
                    default_response_class,

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
```

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

/// tip | "Tipp"

Beachten Sie, dass Sie nicht den Router selbst (`invoices_callback_router`) an `callback=` übergeben, sondern das Attribut `.routes`, wie in `invoices_callback_router.routes`.

///

### Es in der Dokumentation ansehen