এই টাইপগুলি এবং অভ্যন্তরীণ টাইপগুলি ঘোষণা করতে, আপনি Python মডিউল `typing` ব্যবহার করতে পারেন। এটি বিশেষভাবে এই টাইপ হিন্টগুলি সমর্থন করার জন্য রয়েছে।

#### Python এর নতুন সংস্করণ

`typing` ব্যবহার করা সিনট্যাক্সটি Python 3.6 থেকে সর্বশেষ সংস্করণগুলি পর্যন্ত, অর্থাৎ Python 3.9, Python 3.10 ইত্যাদি সহ সকল সংস্করণের সাথে **সামঞ্জস্যপূর্ণ**।

    ```

## `Union` 或者 `anyOf`

响应可以声明为两种类型的 `Union` 类型，即该响应可以是两种类型中的任意类型。

在 OpenAPI 中可以使用 `anyOf` 定义。

为此，请使用 Python 标准类型提示 <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>：

!!! note "笔记"

from typing import Dict

from fastapi import FastAPI

app = FastAPI()


@app.get("/keyword-weights/", response_model=Dict[str, float])
async def read_keyword_weights():

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Union[list[str], None] = Query(default=None)):
    query_items = {"q": q}

from typing import Annotated

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(
    strange_header: Annotated[str | None, Header(convert_underscores=False)] = None,
):

Das wird in OpenAPI mit `anyOf` angezeigt.

Um das zu tun, verwenden Sie Pythons Standard-Typhinweis <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

!!! note "Hinweis"

from typing import Annotated

from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer

app = FastAPI()

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


@app.get("/items/")
async def read_items(token: Annotated[str, Depends(oauth2_scheme)]):

from typing import Annotated

from fastapi import Depends, FastAPI
from fastapi.security import HTTPBasic, HTTPBasicCredentials

app = FastAPI()

security = HTTPBasic()


@app.get("/users/me")
def read_current_user(credentials: Annotated[HTTPBasicCredentials, Depends(security)]):

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class BaseUser(BaseModel):
    username: str
    email: EmailStr
    full_name: Union[str, None] = None


class UserIn(BaseUser):
    password: str


@app.post("/user/")
async def create_user(user: UserIn) -> BaseUser:

from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/")
async def read_items(q: Union[str, None] = None):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})