"""
            ),
        ] = {}
        self.router: routing.APIRouter = routing.APIRouter(
            routes=routes,
            redirect_slashes=redirect_slashes,
            dependency_overrides_provider=self,
            on_startup=on_startup,
            on_shutdown=on_shutdown,

///

### コールバック用ルーターを追加 { #add-the-callback-router }

これで、上で作成したコールバック用ルーター内に、必要なコールバックの *path operation(s)*（*外部開発者* が *外部 API* に実装すべきもの）が用意できました。

次に、*あなたの API の path operation デコレータ*の `callbacks` パラメータに、そのコールバック用ルーターの属性 `.routes`（実体はルート/*path operations* の `list`）を渡します:

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[33] *}

/// tip | 豆知識

import pytest
from fastapi import APIRouter


def test_router_circular_import():
    router = APIRouter()

    with pytest.raises(
        AssertionError,
        match="Cannot include the same APIRouter instance into itself. Did you mean to include a different 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):

@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)

    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

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("/")

from fastapi.testclient import TestClient
from inline_snapshot import snapshot

router = APIRouter()

sub_router = APIRouter()

app = FastAPI()


@sub_router.get("/")
def read_item():
    return {"id": "foo"}


router.include_router(sub_router, prefix="/items")

app.include_router(router)

client = TestClient(app)


def test_path_operation():
    response = client.get("/items/")

Это потому, что у нас также есть другая переменная с именем `router` в подмодуле `users`.

Если бы мы импортировали их одну за другой, как здесь:

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

то `router` из `users` перезаписал бы `router` из `items`, и мы не смогли бы использовать их одновременно.

        )

    return StreamingResponse(iter_data())


app.include_router(
    prefix="/router-scope-function",
    router=router,
    dependencies=[Depends(raise_after_yield, scope="function")],
)

app.include_router(
    prefix="/router-scope-request",
    router=router,
    dependencies=[Depends(raise_after_yield, scope="request")],
)

client = TestClient(app)