}


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    username: str | None = None


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


class UserInDB(User):
    hashed_password: str


password_hash = PasswordHash.recommended()

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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


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


@app.get("/items/")
async def read_items() -> list[Item]:
    return [

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None

    model_config = {
        "json_schema_extra": {
            "examples": [
                {
                    "name": "Foo",
                    "description": "A very nice Item",
                    "price": 35.4,

]


class Author(BaseModel):
    login: str
    avatarUrl: str | None = None
    url: str | None = None


class CommentsNode(BaseModel):
    createdAt: datetime
    author: Author | None = None
    minimizedReason: LowerStr | None = None


class Replies(BaseModel):
    totalCount: int
    nodes: list[CommentsNode]

app = FastAPI()


@app.post("/files/")
async def create_file(file: Annotated[bytes | None, File()] = None):
    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: UploadFile | None = None):
    if not file:
        return {"message": "No upload file sent"}
    else:

例えば、`str` または `None` になり得ることを宣言できます:

```python
from typing import Union


def say_hi(name: Union[str, None]):
        print(f"Hi {name}!")
```

`typing` には、`None` を取り得ることを宣言するための短縮形として `Optional` もあります。

ここからは私のとても主観的な提案です:

- 🚨 `Optional[SomeType]` の使用は避けましょう
- 代わりに ✨ **`Union[SomeType, None]` を使いましょう** ✨。

```Python
say_hi(name=None)  # Це працює, None припустимий 🎉
```

Гарна новина: у більшості випадків ви зможете просто використовувати `|`, щоб визначати об'єднання типів:

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

from pydantic import BaseModel, Field

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = Field(
        default=None, title="The description of the item", max_length=300
    )
    price: float = Field(gt=0, description="The price must be greater than zero")
    tax: float | None = None


@app.put("/items/{item_id}")
async def update_item(item_id: int, item: Annotated[Item, Body(embed=True)]):

app = FastAPI()


class Item(BaseModel):
    name: str | None = None
    description: str | None = None
    price: float | None = None
    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": []},
}

    [
        "array",
        ["string", "null"],
        None,
    ],
)
def test_allowed_schema_type(
    type_value: SchemaType | list[SchemaType] | None,
) -> None:
    """Test that Schema accepts SchemaType, List[SchemaType] and None for type field."""
    schema = Schema(type=type_value)
    assert schema.type == type_value


def test_invalid_type_value() -> None: