"description": "The bartenders",
    "price": 62,
    "tax": 20.2
}
```

they will be included in the response.

#### Data with the same values as the defaults

If the data has the same values as the default ones, like the item with ID `baz`:

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

```Python hl_lines="3  5"
{
    "name": "Bar",
    "description": "The bartenders",
    "price": 62,
    "tax": 20.2
}
```

这些值将包含在响应中。

#### 具有与默认值相同值的数据

如果数据具有与默认值相同的值，例如 ID 为 `baz` 的项：

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

You will also get autocompletion for the payload to send:

<img src="/img/tutorial/generate-clients/image03.png">

/// tip

Notice the autocompletion for `name` and `price`, that was defined in the FastAPI application, in the `Item` model.

///

You will have inline errors for the data that you send:

<img src="/img/tutorial/generate-clients/image04.png">

🖼, 👉 🏷 🔛 📣 🎻 "`object`" (⚖️ 🐍 `dict`) 💖:

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

... `description` & `tax` 📦 (⏮️ 🔢 💲 `None`), 👉 🎻 "`object`" 🔜 ☑:

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

## 📣 ⚫️ 🔢

🚮 ⚫️ 👆 *➡ 🛠️*, 📣 ⚫️ 🎏 🌌 👆 📣 ➡ & 🔢 🔢:

//// tab | 🐍 3️⃣.6️⃣ & 🔛

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

...as `description` and `tax` are optional (with a default value of `None`), this JSON "`object`" would also be valid:

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

## Declare it as a parameter

```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

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

...поскольку `description` и `tax` являются необязательными (с `None` в качестве значения по умолчанию), вот такой JSON "объект" также подходит:

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

## Объявление как параметра функции

Итак, если вы отправите запрос на данную *операцию пути* для элемента, с ID = `Foo` - ответ (с исключенными значениями по-умолчанию) будет таким:

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

/// info | "Информация"

```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):

```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):