class SubItem(BaseModel):
    subname: str
    sub_description: Optional[str] = None
    tags: list[str] = []
    model_config = {"json_schema_serialization_defaults_required": True}


class Item(BaseModel):
    name: str
    description: Optional[str] = None
    sub: Optional[SubItem] = None
    model_config = {"json_schema_serialization_defaults_required": True}


class WithComputedField(BaseModel):

        "required": ["p"],
        "title": body_model_name,
        "type": "object",
    }


@pytest.mark.parametrize("json", [None, {}])
@pytest.mark.parametrize(
    "path",
    ["/required-str", "/model-required-str"],
)
def test_required_str_missing(path: str, json: Union[dict[str, Any], None]):
    client = TestClient(app)
    response = client.post(path, json=json)
    assert response.status_code == 422

async def router_decorator_depends():
    return {"in": "router-decorator-depends"}


app.include_router(router)

client = TestClient(app)


async def overrider_dependency_simple(q: Optional[str] = None):
    return {"q": q, "skip": 5, "limit": 10}


async def overrider_sub_dependency(k: str):
    return {"k": k}


async def overrider_dependency_with_sub(msg: dict = Depends(overrider_sub_dependency)):

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},
    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}

```

////

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"

                """
            ),
        ] = None,
        description: Annotated[
            Optional[str],
            Doc(
                """
                Security scheme description.

                It will be included in the generated OpenAPI (e.g. visible at `/docs`).
                """
            ),
        ] = None,
        auto_error: Annotated[
            bool,
            Doc(

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

        def query_example(
            data: Union[str, None] = Query(
                default=None,
                example="query1",
            ),
        ):
            return data

    @app.get("/query_examples/")
    def query_examples(
        data: Union[str, None] = Query(
            default=None,
            examples=["query1", "query2"],
        ),
    ):

		for i := range erasureDisks[:8] {
			erasureDisks[i] = nil
		}
		return erasureDisks
	}
	z.serverPools[0].erasureDisksMu.Unlock()

	t.Run("if-none-match with read quorum failure", func(t *testing.T) {
		// Test Case 1: if-none-match (create only if doesn't exist)
		// With if-none-match: *, this should only succeed if object doesn't exist.
		// Since read quorum fails, we can't determine if object exists.
		opts := ObjectOptions{

from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"