```Python hl_lines="3  5-6"
{
    "name": "Baz",
    "description": None,
    "price": 50.2,
    "tax": 10.5,
    "tags": []
}
```

from typing import Union

from fastapi import FastAPI
from pydantic.v1 import BaseModel


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    size: float


app = FastAPI()


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

from fastapi import FastAPI
from pydantic import BaseModel


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


app = FastAPI()


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

name: Bug Report
description: Report a bug encountered while operating Kubernetes
labels: kind/bug
body:
  - type: textarea
    id: problem
    attributes:
      label: What happened?
      description: |
        Please provide as much info as possible. Not doing so may result in your bug not being addressed in a timely manner.
        If this matter is security related, please disclose it privately via https://kubernetes.io/security
    validations:

                "get": {
                    "responses": {
                        "200": {
                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {

                "get": {
                    "responses": {
                        "200": {
                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {

                    },
                ],
                "responses": {
                    "200": {
                        "content": {"application/json": {"schema": {}}},
                        "description": "Successful Response",
                    },
                    "422": {
                        "content": {
                            "application/json": {
                                "schema": {

Por exemplo, o modelo acima declara um JSON "`object`" (ou `dict` no Python) como esse:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...como `description` e `tax` são opcionais (com um valor padrão de `None`), esse JSON "`object`" também é válido:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

      },
      "createdTime": {
        "type": "long"
      },
      "updatedBy": {
        "type": "keyword"
      },
      "updatedTime": {
        "type": "long"
      },
      "description" : {
        "type": "text",
        "analyzer": "standard_analyzer"
      }
    }

from fastapi import FastAPI, status
from pydantic import BaseModel

app = FastAPI()


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


@app.post("/items/", response_model=Item, status_code=status.HTTP_201_CREATED)
async def create_item(item: Item):