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:
        results.update({"q": q})

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

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float | None = None
    owner_ids: list[int] | None = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return {"name": "valid", "price": 1.0}


@app.get("/items/coerce", response_model=Item)
def get_coerce():

    return "fakehashed" + password


oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


class User(BaseModel):
    username: str
    email: str | None = None
    full_name: str | None = None
    disabled: bool | None = None


class UserInDB(User):
    hashed_password: str


def get_user(db, username: str):
    if username in db:
        user_dict = db[username]

        ),
    ]


class HTTPBase(SecurityBase):
    model: HTTPBaseModel

    def __init__(
        self,
        *,
        scheme: str,
        scheme_name: str | None = None,
        description: str | None = None,
        auto_error: bool = True,
    ):
        self.model = HTTPBaseModel(scheme=scheme, description=description)
        self.scheme_name = scheme_name or self.__class__.__name__

from pydantic import BaseModel, Field
from starlette.testclient import TestClient

app = FastAPI()


class Item(BaseModel):
    name: str = Field(alias="aliased_name")
    price: float | None = None
    owner_ids: list[int] | None = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return Item(aliased_name="valid", price=1.0)


@app.get("/items/coerce", response_model=Item)
def get_coerce():

```Python
say_hi(name=None)  # Bu çalışır, None geçerlidir 🎉
```

İyi haber şu ki, çoğu durumda tip birliklerini (union) tanımlamak için doğrudan `|` kullanabilirsiniz:

```python
def say_hi(name: str | None):
    print(f"Hey {name}!")
```

@app.get("/query/optional")
def get_query_optional(query=None):
    if query is None:
        return "foo bar"
    return f"foo bar {query}"


@app.get("/query/int")
def get_query_type(query: int):
    return f"foo bar {query}"


@app.get("/query/int/optional")
def get_query_type_optional(query: int | None = None):
    if query is None:
        return "foo bar"
    return f"foo bar {query}"

# Without aliases


@app.post("/optional-list-str", operation_id="optional_list_str")
async def read_optional_list_str(
    p: Annotated[list[str] | None, Form()] = None,
):
    return {"p": p}


class FormModelOptionalListStr(BaseModel):
    p: list[str] | None = None


@app.post("/model-optional-list-str", operation_id="model_optional_list_str")

    type: SchemaType | list[SchemaType] | None = None
    enum: list[Any] | None = None
    const: Any | None = None
    multipleOf: float | None = Field(default=None, gt=0)
    maximum: float | None = None
    exclusiveMaximum: float | None = None
    minimum: float | None = None
    exclusiveMinimum: float | None = None
    maxLength: int | None = Field(default=None, ge=0)
    minLength: int | None = Field(default=None, ge=0)

O parâmetro `name` continua obrigatório (não é opcional) porque não tem valor padrão. Ainda assim, `name` aceita `None` como valor:

```Python
say_hi(name=None)  # Isso funciona, None é válido 🎉
```

A boa notícia é que, na maioria dos casos, você poderá simplesmente usar `|` para definir uniões de tipos:

```python
def say_hi(name: str | None):
    print(f"Hey {name}!")
```