from starlette.status import HTTP_401_UNAUTHORIZED


class APIKeyBase(SecurityBase):
    def __init__(
        self,
        location: APIKeyIn,
        name: str,
        description: Union[str, None],
        scheme_name: Union[str, None],
        auto_error: bool,
    ):
        self.auto_error = auto_error

        self.model: APIKey = APIKey(
            **{"in": location},
            name=name,

            200,
            {"q_or_cookie": "foo"},
        ),
        (
            "/items",
            None,
            200,
            {"q_or_cookie": None},
        ),
    ],
)
def test_get(path, cookie, expected_status, expected_response, client: TestClient):
    if cookie is not None:
        client.cookies.set("last_query", cookie)
    else:
        client.cookies.clear()
    response = client.get(path)

    assert response.json() == {
        "detail": [
            {
                "type": "missing",
                "loc": ["cookie", "p"],
                "msg": "Field required",
                "input": IsOneOf(None, {}),
            }
        ]
    }


@pytest.mark.parametrize(
    "path",
    ["/required-str", "/model-required-str"],
)
def test_required_str(path: str):
    client = TestClient(app)

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(user_agent: str | None = Header(default=None)):

{!> ../../docs_src/python_types/tutorial008b_py39.py!}
```

////

In both cases this means that `item` could be an `int` or a `str`.

#### Possibly `None` { #possibly-none }

You can declare that a value could have a type, like `str`, but that it could also be `None`.

In Python 3.6 and above (including Python 3.10) you can declare it by importing and using `Optional` from the `typing` module.

```Python hl_lines="1  4"

from typing import Annotated

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None


@app.put("/items/{item_id}")
async def update_item(
    item_id: int,
    item: Annotated[
        Item,
        Body(
            examples=[
                {

app = FastAPI()


@app.post("/files/")
async def create_file(file: Union[bytes, None] = File(default=None)):
    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: Union[UploadFile, None] = None):
    if not file:
        return {"message": "No upload file sent"}
    else:

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(x_token: list[str] | None = Header(default=None)):

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: list[str] | None = Query(default=None)):
    query_items = {"q": q}

from typing import Any

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None
    tags: list[str] = []


@app.post("/items/", response_model=Item)
async def create_item(item: Item) -> Any:
    return item


@app.get("/items/", response_model=list[Item])