<td><c:forEach var="rt" varStatus="s"
                                                       items="${roleItems}">
                                            <c:forEach var="rtid" varStatus="s" items="${roles}">
                                                <c:if test="${rtid==rt.id}">
                                                    ${f:h(rt.name)}<br/>

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

{* ../../docs_src/body_nested_models/tutorial003_py310.py hl[12] *}

With this, even if you receive a request with duplicate data, it will be converted to a set of unique items.

And whenever you output that data, even if the source had duplicates, it will be output as a set of unique items.

) -> dict[Callable[[Any], Any], tuple[Any, ...]]:
    encoders_by_class_tuples: dict[Callable[[Any], Any], tuple[Any, ...]] = defaultdict(
        tuple
    )
    for type_, encoder in type_encoder_map.items():
        encoders_by_class_tuples[encoder] += (type_,)
    return encoders_by_class_tuples


encoders_by_class_tuples = generate_encoders_by_class_tuples(ENCODERS_BY_TYPE)


def jsonable_encoder(

    openapi = app.openapi()
    body_model_name = get_body_model_name(openapi, path)

    assert app.openapi()["components"]["schemas"][body_model_name] == {
        "properties": {
            "p": {
                "items": {"type": "string"},
                "title": "P",
                "type": "array",
            },
        },
        "required": ["p"],
        "title": body_model_name,
        "type": "object",
    }

/// tip

您可以在 `description` 字段中编写 Markdown，它将在输出中呈现。

///

通过这样设置，自动 API 文档看起来会像：

<img src="/img/tutorial/metadata/image01.png">

## 标签元数据

### 创建标签元数据

让我们在带有标签的示例中为 `users` 和 `items` 试一下。

创建标签元数据并把它传递给 `openapi_tags` 参数：

{* ../../docs_src/metadata/tutorial004.py hl[3:16,18] *}

注意你可以在描述内使用 Markdown，例如「login」会显示为粗体（**login**）以及「fancy」会显示为斜体（_fancy_）。

/// tip | 提示

不必为你使用的所有标签都添加元数据。

def process_items(prices: dict[str, float]):
    for item_name, item_price in prices.items():
        print(item_name)

    System.out.println(response.getContentAsString());
}
```

### Asynchronous request

```java
import org.codelibs.curl.Curl;

Curl.post("https://api.example.com/items")
    .body("{\"name\":\"item1\"}")
    .header("Content-Type", "application/json")
    .execute(
        response -> System.out.println("Async status: " + response.getHttpStatusCode()),

Por ejemplo, si el cliente intenta enviar un parámetro query `tool` con un valor de `plumbus`, como:

```http
https://example.com/items/?limit=10&tool=plumbus
```

Recibirán un response de **error** que les indica que el parámetro query `tool` no está permitido:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/", include_in_schema=False)
async def read_items():

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/{item_id}")
async def read_item(item_id):