"PlaneItem": {
                    "title": "PlaneItem",
                    "required": IsOneOf(
                        ["description", "type", "size"],
                        # TODO: remove when deprecating Pydantic v1
                        ["description", "size"],
                    ),
                    "type": "object",
                    "properties": {

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class UserIn(BaseModel):
    username: str
    password: str
    email: EmailStr
    full_name: str | None = None


class UserOut(BaseModel):
    username: str
    email: EmailStr
    full_name: str | None = None


class UserInDB(BaseModel):
    username: str
    hashed_password: str
    email: EmailStr

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 Optional

from fastapi import Depends, FastAPI
from pydantic import BaseModel, validator

app = FastAPI()


class ModelB(BaseModel):
    username: str


class ModelC(ModelB):
    password: str


class ModelA(BaseModel):
    name: str
    description: Optional[str] = None
    model_b: ModelB

    @validator("name")
    def lower_username(cls, name: str, values):

from typing import Annotated

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


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


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


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,

```

////

/// tip

Pydantic, ❔ ⚫️❔ 🏋️ 🌐 💽 🔬 &amp; 🛠️ FastAPI, ✔️ 🎁 🎭 🕐❔ 👆 ⚙️ `Optional` ⚖️ `Union[Something, None]` 🍵 🔢 💲, 👆 💪 ✍ 🌅 🔃 ⚫️ Pydantic 🩺 🔃 <a href="https://docs.pydantic.dev/latest/concepts/models/#required-optional-fields" class="external-link" target="_blank">✔ 📦 🏑</a>.

///

### ⚙️ Pydantic `Required` ↩️ ❕ (`...`)

Jedes dieser Response-`dict`s kann einen Schlüssel `model` haben, welcher ein Pydantic-Modell enthält, genau wie `response_model`.

**FastAPI** nimmt dieses Modell, generiert dessen JSON-Schema und fügt es an der richtigen Stelle in OpenAPI ein.

Um beispielsweise eine weitere Response mit dem Statuscode `404` und einem Pydantic-Modell `Message` zu deklarieren, können Sie schreiben:

```Python hl_lines="18  22"

Each of those response `dict`s can have a key `model`, containing a Pydantic model, just like `response_model`.

**FastAPI** will take that model, generate its JSON Schema and include it in the correct place in OpenAPI.

For example, to declare another response with a status code `404` and a Pydantic model `Message`, you can write:

{* ../../docs_src/additional_responses/tutorial001.py hl[18,22] *}

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


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


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,

///

그리고 `Response`를 반환하면 **FastAPI**가 이를 그대로 전달합니다.

Pydantic 모델로 데이터 변환을 수행하지 않으며, 내용을 다른 형식으로 변환하지 않습니다.

이로 인해 많은 유연성을 얻을 수 있습니다. 어떤 데이터 유형이든 반환할 수 있고, 데이터 선언이나 유효성 검사를 재정의할 수 있습니다.

## `Response`에서 `jsonable_encoder` 사용하기

**FastAPI**는 반환하는 `Response`에 아무런 변환을 하지 않으므로, 그 내용이 준비되어 있어야 합니다.

예를 들어, Pydantic 모델을 `dict`로 변환해 `JSONResponse`에 넣지 않으면 JSON 호환 유형으로 변환된 데이터 유형(예: `datetime`, `UUID` 등)이 사용되지 않습니다.