class Image(BaseModel):
    url: HttpUrl
    name: str


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: set[str] = set()
    images: Union[list[Image], None] = None


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

app = FastAPI()


class Image(BaseModel):
    url: HttpUrl
    name: str


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


class Offer(BaseModel):
    name: str
    description: str | None = None
    price: float
    items: list[Item]


@app.post("/offers/")

<?xml version="1.0" encoding="UTF-8"?>
<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
  <ShortName>Fess</ShortName>
  <Description>Full Text Search for Your Documents.</Description>
  <Tags>Full Text Search</Tags>
  <Contact>******@****.***</Contact>
  <SearchForm>http://localhost:8080/fess/</SearchForm>
  <Url type="text/html" template="http://localhost:8080/fess/search?q={searchTerms}"/>
  <InputEncoding>UTF-8</InputEncoding>

```

////

//// tab | Python 3.8+

```Python hl_lines="14"
{!> ../../docs_src/body_nested_models/tutorial001.py!}
```

////

Это приведёт к тому, что обьект `tags` преобразуется в список, несмотря на то что тип его элементов не объявлен.

## Определение полей содержащих список с определением типов его элементов

내부 타입을 갖는 모델 어트리뷰트에 대해 동일한 표준 문법을 사용하세요.

마찬가지로 예제에서 `tags`를 구체적으로 "문자열의 리스트"로 만들 수 있습니다:

```Python hl_lines="14"
{!../../docs_src/body_nested_models/tutorial002.py!}
```

## 집합 타입

그런데 생각해보니 태그는 반복되면 안 되고, 고유한(Unique) 문자열이어야 할 것 같습니다.

그리고 파이썬은 집합을 위한 특별한 데이터 타입 `set`이 있습니다.

그렇다면 `Set`을 임포트 하고 `tags`를 `str`의 `set`으로 선언할 수 있습니다:

```Python hl_lines="1  14"

class Image(BaseModel):
    url: HttpUrl
    name: str


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: Set[str] = set()
    images: Union[List[Image], None] = None


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

            tagClass = header.tagClass,
            tag = header.tag,
            constructed = header.constructed,
            length = header.length,
            bytes = bytes,
          )
        }
      }

      override fun toDer(
        writer: DerWriter,
        value: AnyValue,
      ) {
        writer.write("ANY", value.tagClass, value.tag) {
          writer.writeOctetString(value.bytes)

	FailurePolicy map[string]*admitv1.FailurePolicyType
}

// GenerateOptions is the group of options needed to generate a tag webhook.
type GenerateOptions struct {
	// Tag is the name of the revision tag to generate.
	Tag string
	// Revision is the revision to associate the revision tag with.
	Revision string
	// WebhookName is an override for the mutating webhook name.
	WebhookName string

    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5
    tags: List[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},
    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}


@app.get("/items/{item_id}", response_model=Item, response_model_exclude_unset=True)

    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/": {
                "get": {
                    "tags": ["items"],
                    "summary": "Get Items",
                    "operationId": "items-get_items",
                    "responses": {
                        "200": {