@dataclass
class Item:
    name: str
    description: str | None = None


@dataclass
class Author:
    name: str
    items: list[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)
async def create_author_items(author_id: str, items: list[Item]):  # (5)

@dataclass
class Item:
    name: str
    description: Union[str, None] = None


@dataclass
class Author:
    name: str
    items: list[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)
async def create_author_items(author_id: str, items: list[Item]):  # (5)

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel


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


app = FastAPI()


@app.post("/items/")
async def create_item(item: Item):

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The Bar fighters", "price": 62, "tax": 20.2},
    "baz": {
        "name": "Baz",

from pydantic import BaseModel, SecretStr
from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    github_repository: str
    github_token: SecretStr


class Repo(BaseModel):
    name: str
    html_url: str
    stars: int
    owner_login: str
    owner_html_url: str


def main() -> None:
    logging.basicConfig(level=logging.INFO)
    settings = Settings()

        String str = info.toString();

        // Verify string contains expected elements
        assertNotNull(str);
        assertTrue(str.startsWith("SmbQueryFileBasicInfo["));
        assertTrue(str.contains("createTime="));
        assertTrue(str.contains("lastAccessTime="));
        assertTrue(str.contains("lastWriteTime="));
        assertTrue(str.contains("changeTime="));

```Python hl_lines="1"
async def needy_dependency(fresh_value: Annotated[str, Depends(get_value, use_cache=False)]):
    return {"fresh_value": fresh_value}
```

////

//// tab | Python 3.9+ sin Anotaciones

/// tip | Consejo

Prefiere usar la versión `Annotated` si es posible.

///

```Python hl_lines="1"
async def needy_dependency(fresh_value: str = Depends(get_value, use_cache=False)):

from typing import Optional


def get_authorization_scheme_param(
    authorization_header_value: Optional[str],
) -> tuple[str, str]:
    if not authorization_header_value:
        return "", ""
    scheme, _, param = authorization_header_value.partition(" ")

    b: Annotated[float, Body(allow_inf_nan=False)] = 0,
) -> str:
    return "OK"


client = TestClient(app)


@pytest.mark.parametrize(
    "value,code",
    [
        ("-1", 200),
        ("inf", 200),
        ("-inf", 200),
        ("nan", 200),
        ("0", 200),
        ("342", 200),
    ],
)
def test_allow_inf_nan_param_true(value: str, code: int):
    response = client.post(f"/?x={value}")

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009_py39.py!}
```

Использование `Optional[str]` вместо просто `str` позволит редактору кода помочь вам обнаружить ошибки, когда вы предполагаете, что значение всегда `str`, хотя на самом деле оно может быть и `None`.

`Optional[Something]` — это на самом деле сокращение для `Union[Something, None]`, они эквивалентны.