SpliteratorTester.of(
            () ->
                CollectSpliterators.flatMap(
                    Arrays.spliterator(new String[] {"abc", "", "de", "f", "g", ""}),
                    (String str) -> str.isEmpty() ? null : charactersOf(str).spliterator(),
                    Spliterator.SIZED | Spliterator.DISTINCT | Spliterator.NONNULL,
                    7))
        .expect('a', 'b', 'c', 'd', 'e', 'f', 'g');
  }

app = FastAPI()


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


@app.put("/items/{item_id}")
async def update_item(
    item_id: Annotated[int, Path(title="The ID of the item to get", ge=0, le=1000)],
    q: Union[str, None] = None,
    item: Union[Item, None] = None,
):
    results = {"item_id": item_id}

from typing import Set, Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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


@app.post(
    "/items/",
    response_model=Item,
    summary="Create an item",

app = FastAPI()


@app.get("/default")
async def default(foo: Annotated[str, Query()] = "foo"):
    return {"foo": foo}


@app.get("/required")
async def required(foo: Annotated[str, Query(min_length=1)]):
    return {"foo": foo}


@app.get("/multiple")
async def multiple(foo: Annotated[str, object(), Query(min_length=1)]):
    return {"foo": foo}


@app.get("/unrelated")

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: Union[float, None] = None
    tags: set[str] = set()


@app.post("/items/", response_model=Item, summary="Create an item")
async def create_item(item: Item):
    """
    Create an item with all the information:

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: Union[float, None] = None
    tags: set[str] = set()


@app.post("/items/", response_model=Item, tags=["items"])
async def create_item(item: Item):
    return item


@app.get("/items/", tags=["items"])

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

O uso de `Optional[str]` em vez de apenas `str` permitirá que o editor o ajude a detectar erros, onde você pode estar assumindo que um valor é sempre um `str`, quando na verdade também pode ser `None`.

`Optional[Something]` é na verdade um atalho para `Union[Something, None]`, eles são equivalentes.

Isso também significa que no Python 3.10, você pode utilizar `Something | None`:

                    String server = str.substring(mark, si).trim();
                    if ( server.length() == 0 ) {
                        // this can also be a v6 address within brackets, look ahead required
                        int nexts = str.indexOf('[', si + 1);
                        int nexte = str.indexOf(']', si);
                        if ( nexts >= 0 && nexte >= 0 && nexte == nexts - 1 ) {

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: Annotated[int, Path(title="The ID of the item to get", ge=0, le=1000)],
    q: str | None = None,
    item: Item | None = None,
):
    results = {"item_id": item_id}
    if q:

    response.set_cookie("cookie-name", "cookie-value")
    return {}


def set_indirect_cookie(*, dep: str = Depends(set_cookie)):
    return dep


@app.get("/directCookie")
def get_direct_cookie(dep: str = Depends(set_cookie)):
    return {"dep": dep}


@app.get("/indirectCookie")
def get_indirect_cookie(dep: str = Depends(set_indirect_cookie)):
    return {"dep": dep}


client = TestClient(app)