そして、それを属性の型として使用することができます:

{* ../../docs_src/body_nested_models/tutorial004.py hl[20] *}

これは **FastAPI** が以下のようなボディを期待することを意味します:

```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"
    }
}
```

*  `prices` değişkeni `dict` tipindedir:
    *  `dict` değişkeninin `key` değeri  `str` tipindedir (herbir item'ın "name" değeri).
    *  `dict` değişkeninin `value` değeri `float` tipindedir (lherbir item'ın "price" değeri).

#### `Optional`

`Optional` bir değişkenin `str`gibi bir tipi olabileceğini ama isteğe bağlı olarak tipinin `None` olabileceğini belirtir:

```Python hl_lines="1  4"

 *
 * <p>This class should not be assumed to be universally superior to {@code
 * java.util.LinkedHashSet}. Generally speaking, this class reduces object allocation and memory
 * consumption at the price of moderately increased constant factors of CPU. Only use this class
 * when there is a specific reason to prioritize memory over CPU.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible // not worth using in GWT for now

*  <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">🗒</a>:

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

👆 🔜 🤚 🛠️ 📟 👆 5️⃣📆 🤔 💪 ⏭. 🖼, `price` 🔑 🔘 🎻 💪 (👈 💪 ✔️ 🐦) 👈 👟 ⚪️➡️ 📨.

🙅‍♂ 🌖 ⌨ ❌ 🔑 📛, 👟 🔙 &amp; ➡ 🖖 🩺, ⚖️ 📜 🆙 &amp; 🔽 🔎 🚥 👆 😒 ⚙️ `username` ⚖️ `user_name`.

### 📏

```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):

![editor ondersteuning](https://fastapi.tiangolo.com/img/pycharm-completion.png)

Je krijgt autocomletion die je voorheen misschien zelfs voor onmogelijk had gehouden. Zoals bijvoorbeeld de `price` key in een JSON body (die genest had kunnen zijn) die afkomstig is van een request.

{* ../../docs_src/body_updates/tutorial001.py hl[30,31,32,33,34,35] *}

既存のデータを置き換えるべきデータを受け取るために`PUT`は使用されます。

### 置換についての注意

つまり、`PUT`を使用して以下のボディで項目`bar`を更新したい場合は:

```Python
{
    "name": "Barz",
    "price": 3,
    "description": None,
}
```

すでに格納されている属性`"tax": 20.2`を含まないため、入力モデルのデフォルト値は`"tax": 10.5`です。

そして、データはその「新しい」`10.5`の`tax`と共に保存されます。

## `PATCH`による部分的な更新

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

Вы будете получать автодополнение кода даже там, где вы считали это невозможным раньше.
Как пример, ключ `price` внутри тела JSON (который может быть вложенным), приходящего в запросе.

 *
 * <p>This class should not be assumed to be universally superior to {@code java.util.HashSet}.
 * Generally speaking, this class reduces object allocation and memory consumption at the price of
 * moderately increased constant factors of CPU. Only use this class when there is a specific reason
 * to prioritize memory over CPU.
 *
 * @author Dimitris Andreou
 * @author Jon Noack
 */

   */
  public List<Long> asList() {
    /*
     * Typically we cache this kind of thing, but much repeated use of this view is a performance
     * anti-pattern anyway. If we cache, then everyone pays a price in memory footprint even if
     * they never use this method.
     */
    return new AsList(this);
  }

  private static final class AsList extends AbstractList<Long>