dunder_call = getattr(_impartial(self.call), "__call__", None)  # noqa: B004
        if dunder_call is None:
            return False  # pragma: no cover
        if inspect.isgeneratorfunction(
            _impartial(dunder_call)
        ) or inspect.isgeneratorfunction(_unwrapped_call(dunder_call)):
            return True
        dunder_unwrapped_call = getattr(_unwrapped_call(self.call), "__call__", None)  # noqa: B004

from typing import Annotated

from fastapi import Depends, FastAPI

app = FastAPI()


class FixedContentQueryChecker:
    def __init__(self, fixed_content: str):
        self.fixed_content = fixed_content

    def __call__(self, q: str = ""):
        if q:
            return self.fixed_content in q
        return False


checker = FixedContentQueryChecker("bar")


@app.get("/query-checker/")

        return HTTPException(
            status_code=HTTP_401_UNAUTHORIZED,
            detail="Not authenticated",
            headers=self.make_authenticate_headers(),
        )

    async def __call__(self, request: Request) -> HTTPAuthorizationCredentials | None:
        authorization = request.headers.get("Authorization")
        scheme, credentials = get_authorization_scheme_param(authorization)

from fastapi import Depends, FastAPI

app = FastAPI()


class FixedContentQueryChecker:
    def __init__(self, fixed_content: str):
        self.fixed_content = fixed_content

    def __call__(self, q: str = ""):
        if q:
            return self.fixed_content in q
        return False


checker = FixedContentQueryChecker("bar")


@app.get("/query-checker/")

            location=APIKeyIn.query,
            name=name,
            scheme_name=scheme_name,
            description=description,
            auto_error=auto_error,
        )

    async def __call__(self, request: Request) -> str | None:
        api_key = request.query_params.get(self.model.name)
        return self.check_api_key(api_key)


class APIKeyHeader(APIKeyBase):
    """

                        "code": 999,
                        "message": "File limit exceeded",
                    },
                )
            return message

        return inner

    async def __call__(self, scope, receive, send):
        if scope["type"] != "http" or self.max_content_size is None:
            await self.app(scope, receive, send)
            return

        wrapper = self.receive_wrapper(receive)

Not the class itself (which is already a callable), but an instance of that class.

To do that, we declare a method `__call__`:

{* ../../docs_src/dependencies/tutorial011_an_py310.py hl[12] *}

        return HTTPException(
            status_code=HTTP_401_UNAUTHORIZED,
            detail="Not authenticated",
            headers={"WWW-Authenticate": "Bearer"},
        )

    async def __call__(self, request: Request) -> str | None:
        authorization = request.headers.get("Authorization")
        if not authorization:
            if self.auto_error:
                raise self.make_not_authenticated_error()

        """
        return HTTPException(
            status_code=HTTP_401_UNAUTHORIZED,
            detail="Not authenticated",
            headers={"WWW-Authenticate": "Bearer"},
        )

    async def __call__(self, request: Request) -> str | None:
        authorization = request.headers.get("Authorization")
        if not authorization:
            if self.auto_error:
                raise self.make_not_authenticated_error()

## "callable" なインスタンス { #a-callable-instance }

Python には、クラスのインスタンスを "callable" にする方法があります。

クラス自体（これはすでに callable です）ではなく、そのクラスのインスタンスです。

そのためには、`__call__` メソッドを宣言します:

{* ../../docs_src/dependencies/tutorial011_an_py310.py hl[12] *}

この場合、この `__call__` が、**FastAPI** が追加のパラメータやサブ依存関係を確認するために使うものになり、後であなたの *path operation 関数* のパラメータに値を渡すために呼び出されるものになります。

## インスタンスのパラメータ化 { #parameterize-the-instance }