"loc": ["header", "x-token"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "missing",
                    "loc": ["header", "x-key"],
                    "msg": "Field required",
                    "input": None,
                },
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

        )

        # Update a hero
        response = client.patch(
            f"/heroes/{hero_id}", json={"name": "Dog Pond", "age": None}
        )
        assert response.status_code == 200, response.text
        assert response.json() == snapshot(
            {"name": "Dog Pond", "age": None, "id": hero_id}
        )

        # Get updated hero
        response = client.get(f"/heroes/{hero_id}")

                    "loc": ["header", "x-token"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "missing",
                    "loc": ["header", "x-key"],
                    "msg": "Field required",
                    "input": None,
                },
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1

`Optional[Something]` насправді є скороченням для `Union[Something, None]`, вони еквівалентні.

Це також означає, що в Python 3.10 ви можете використовувати `Something | None`:

//// tab | Python 3.8 і вище

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009.py!}
```

    "path,expected_status,expected_response",
    [
        ("/items", 200, {"q": None, "skip": 0, "limit": 100}),
        ("/items?q=foo", 200, {"q": "foo", "skip": 0, "limit": 100}),
        ("/items?q=foo&skip=5", 200, {"q": "foo", "skip": 5, "limit": 100}),
        ("/items?q=foo&skip=5&limit=30", 200, {"q": "foo", "skip": 5, "limit": 30}),
        ("/users", 200, {"q": None, "skip": 0, "limit": 100}),
    ],
)

    response = client.get("/items/foo?needy=very")
    assert response.status_code == 200
    assert response.json() == {
        "item_id": "foo",
        "needy": "very",
        "skip": 0,
        "limit": None,
    }


def test_foo_no_needy(client: TestClient):
    response = client.get("/items/foo?skip=a&limit=b")
    assert response.status_code == 422
    assert response.json() == IsDict(
        {

    else:

        class Config:
            extra = "forbid"


class Foo(FooBaseModel):
    pass


app = FastAPI()


@app.post("/")
async def post(
    foo: Union[Foo, None] = None,
):
    return foo


client = TestClient(app)


def test_call_invalid():
    response = client.post("/", json={"foo": {"bar": "baz"}})
    assert response.status_code == 422

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel, ConfigDict

from .utils import needs_pydanticv1, needs_pydanticv2


@needs_pydanticv2
def test_read_with_orm_mode() -> None:
    class PersonBase(BaseModel):
        name: str
        lastname: str

    class Person(PersonBase):
        @property
        def full_name(self) -> str:
            return f"{self.name} {self.lastname}"

    assert response.status_code == 200, response.text
    assert response.json() == {
        "name": "Foo",
        "price": 42,
        "description": None,
        "tax": None,
        "tags": [],
    }


@needs_py39
@needs_pydanticv2
def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")