app = FastAPI()


@app.get("/items/")
def read_items(q: Optional[str] = Param(default=None)):  # type: ignore
    return {"q": q}


client = TestClient(app)


def test_default_param_query_none():
    response = client.get("/items/")
    assert response.status_code == 200, response.text
    assert response.json() == {"q": None}


def test_default_param_query():
    response = client.get("/items/?q=foo")

from fastapi import Depends, FastAPI

app = FastAPI()


fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]


class CommonQueryParams:
    def __init__(self, q: str | None = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit


@app.get("/items/")
async def read_items(commons: Annotated[Any, Depends(CommonQueryParams)]):

		echo retry: timeout while running: mc alias set
		exit 1
	fi
	eval ./mc alias set "${ALIAS_NAME}" "${MINIO_SERVER_URL}" minioadmin minioadmin && break
	TIMEOUT=$((TIMEOUT - 1))
	sleep 1
done

./mc ready "${ALIAS_NAME}"

./mc mb "${ALIAS_NAME}"/"${BUCKET}"
rm -rf "${SRC_DIR}" "${INLINED_DIR}" "${DEST_DIR}" && mkdir -p "${SRC_DIR}" "${INLINED_DIR}" "${DEST_DIR}"
for idx in {1..10}; do

from typing import Optional


def say_hi(name: Optional[str] = None):
    if name is not None:
        print(f"Hey {name}!")
    else:

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(
    strange_header: str | None = Header(default=None, convert_underscores=False),
):

```

////

В обоих случаях это означает, что `item` может быть `int` или `str`.

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

Вы можете объявить, что значение может иметь определённый тип, например `str`, но также может быть и `None`.

В Python 3.6 и выше (включая Python 3.10) это можно объявить, импортировав и используя `Optional` из модуля `typing`.

```Python hl_lines="1  4"

		aws --endpoint-url http://localhost:"$start_port" s3api upload-part \
			--upload-id "$uploadId" --bucket bucket --key obj-1 \
			--part-number "$i" --body ./file-5mib
	done
	for i in {1..6}; do
		find ${WORK_DIR}/disk${i}/.minio.sys/multipart/ -type f -name "part.1" -delete
	done
	cat <<EOF >parts.json
{
    "Parts": [
        {
            "PartNumber": 1,
            "ETag": "5f363e0e58a95f06cbe9bbc662c5dfb6"
        },

echo "done"

if [ ! -f ./mc ]; then
	echo -n "Downloading MinIO client ..."
	wget -O mc https://dl.min.io/client/mc/release/linux-amd64/mc &&
		chmod +x mc
	echo "done"
fi

export MC_HOST_minio1=https://minio:minio123@localhost:9001
export MC_HOST_minio2=https://minio:minio123@localhost:9002

from typing import Annotated

from fastapi import Cookie, FastAPI

app = FastAPI()


@app.get("/items/")
async def read_items(ads_id: Annotated[str | None, Cookie()] = None):

FastAPI weiß, dass der Wert von `q` nicht erforderlich ist, aufgrund des definierten Defaultwertes `= None`.

Das `str | None` (Python 3.10+) oder `Union` in `Union[str, None]` (Python 3.9+) wird von FastAPI nicht verwendet, um zu bestimmen, dass der Wert nicht erforderlich ist. FastAPI weiß, dass er nicht erforderlich ist, weil er einen Defaultwert von `= None` hat.