def _annotation_is_complex(annotation: Union[type[Any], None]) -> bool:
    return (
        lenient_issubclass(annotation, (BaseModel, Mapping, UploadFile))
        or _annotation_is_sequence(annotation)
        or is_dataclass(annotation)
    )


def field_annotation_is_complex(annotation: Union[type[Any], None]) -> bool:
    origin = get_origin(annotation)
    if origin is Union or origin is UnionType:

from fastapi import FastAPI, Path
from pydantic import BaseModel

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: int = Path(title="The ID of the item to get", ge=0, le=1000),
    q: Union[str, None] = None,

            main_dict[key] = main_dict[key] + update_dict[key]
        else:
            main_dict[key] = value


def get_value_or_default(
    first_item: Union[DefaultPlaceholder, DefaultType],
    *extra_items: Union[DefaultPlaceholder, DefaultType],
) -> Union[DefaultPlaceholder, DefaultType]:
    """
    Pass items or `DefaultPlaceholder`s by descending priority.

## `Union` or `anyOf` { #union-or-anyof }

You can declare a response to be the `Union` of two or more types, that means, that the response would be any of them.

It will be defined in OpenAPI with `anyOf`.

To do that, use the standard Python type hint <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

/// note

}


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


class TokenData(BaseModel):
    username: Union[str, None] = None


class User(BaseModel):
    username: str
    email: Union[str, None] = None
    full_name: Union[str, None] = None
    disabled: Union[bool, None] = None


class UserInDB(User):
    hashed_password: str


password_hash = PasswordHash.recommended()

            ),
        ] = None,
        discriminator: Union[str, None] = None,
        strict: Union[bool, None] = _Unset,
        multiple_of: Union[float, None] = _Unset,
        allow_inf_nan: Union[bool, None] = _Unset,
        max_digits: Union[int, None] = _Unset,
        decimal_places: Union[int, None] = _Unset,
        examples: Optional[list[Any]] = None,
        example: Annotated[

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 Body, FastAPI
from pydantic import BaseModel

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: int,
    item: Item = Body(
        examples=[
            {
                "name": "Foo",

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel, Field

app = FastAPI()


class Item(BaseModel):
    name: str = Field(examples=["Foo"])
    description: Union[str, None] = Field(default=None, examples=["A very nice Item"])
    price: float = Field(examples=[35.4])
    tax: Union[float, None] = Field(default=None, examples=[3.2])


@app.put("/items/{item_id}")

    headers: Optional[dict[str, Union[Header, Reference]]] = None
    securitySchemes: Optional[dict[str, Union[SecurityScheme, Reference]]] = None
    links: Optional[dict[str, Union[Link, Reference]]] = None
    # Using Any for Specification Extensions
    callbacks: Optional[dict[str, Union[dict[str, PathItem], Reference, Any]]] = None
    pathItems: Optional[dict[str, Union[PathItem, Reference]]] = None