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

...так как `description` и `tax` являются необязательными (со значением по умолчанию `None`), такой JSON "объект" тоже будет корректным:

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

## Объявите её как параметр { #declare-it-as-a-parameter }

{* ../../docs_src/body_nested_models/tutorial004_py310.py hl[18] *}

Це означатиме, що  **FastAPI**  очікуватиме тіло запиту такого вигляду:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

{* ../../docs_src/body_nested_models/tutorial004_py310.py hl[18] *}

This would mean that **FastAPI** would expect a body similar to:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

{* ../../docs_src/body_nested_models/tutorial004_py310.py hl[18] *}

Это означает, что **FastAPI** будет ожидать тело запроса, аналогичное этому:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

{* ../../docs_src/body_nested_models/tutorial004_py310.py hl[18] *}

Esto significaría que **FastAPI** esperaría un cuerpo similar a:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

```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
}
```

## Declare como um parâmetro { #declare-it-as-a-parameter }

```Python hl_lines="4  9-12  25-27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):

So, if you send a request to that *path operation* for the item with ID `foo`, the response (not including default values) will be:

```JSON
{
    "name": "Foo",
    "price": 50.2
}
```

/// info

You can also use:

* `response_model_exclude_defaults=True`
* `response_model_exclude_none=True`

Então, se você enviar uma solicitação para essa *operação de rota* para o item com ID `foo`, a resposta (sem incluir valores padrão) será:

```JSON
{
    "name": "Foo",
    "price": 50.2
}
```

/// info | Informação

No Pydantic v1, o método era chamado `.dict()`, ele foi descontinuado (mas ainda suportado) no Pydantic v2 e renomeado para `.model_dump()`.

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

...`description` et `tax` étant des attributs optionnels (avec `None` comme valeur par défaut), cet "objet" JSON serait aussi valide :

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

## Déclarez-le comme paramètre