"properties": {
                        "loc": {
                            "title": "Location",
                            "type": "array",
                            "items": {
                                "anyOf": [{"type": "string"}, {"type": "integer"}]
                            },
                        },
                        "msg": {"title": "Message", "type": "string"},

                    "properties": {
                        "loc": {
                            "title": "Location",
                            "type": "array",
                            "items": {
                                "anyOf": [{"type": "string"}, {"type": "integer"}]
                            },
                        },
                        "msg": {"title": "Message", "type": "string"},

	<c:if test="${crudMode == null}">
		<li class="breadcrumb-item active"><la:message key="labels.crud_link_list" /></li>
	</c:if>
	<c:if test="${crudMode != null}">
		<li class="breadcrumb-item"><la:link href="../list">
				<la:message key="labels.crud_link_list" />
			</la:link></li>
	</c:if>
	<c:if test="${crudMode == 1}">
		<li class="breadcrumb-item active"><la:message key="labels.crud_link_create" /></li>
	</c:if>

                                        <td><c:forEach var="l" varStatus="s"
                                                       items="${labelTypeItems}">
                                            <c:forEach var="ltid" varStatus="s"
                                                       items="${labelTypeIds}">
                                                <c:if test="${ltid==l.id}">

                                            <c:forEach var="p" varStatus="s"
                                                       items="${pager.pageNumberList}">
                                                <li
                                                        <c:if test="${p == pager.currentPageNumber}">class="page-item active"</c:if>>
                                                    <la:link

                                            <c:forEach var="l" varStatus="s"
                                                       items="${labelTypeItems}">
                                                <c:forEach var="ltid" varStatus="s"
                                                           items="${labelTypeIds}">
                                                    <c:if test="${ltid==l.id}">

```

1. 本例依然要从标准的 `dataclasses` 中导入 `field`；

2. 使用 `pydantic.dataclasses` 直接替换 `dataclasses`；

3. `Author` 数据类包含 `Item` 数据类列表；

4. `Author` 数据类用于 `response_model` 参数；

5. 其它带有数据类的标准类型注解也可以作为请求体；

    本例使用的是 `Item` 数据类列表；

6. 这行代码返回的是包含 `items` 的字典，`items` 是数据类列表；

    FastAPI 仍能把数据<abbr title="把数据转换为可以传输的格式">序列化</abbr>为 JSON；

7. 这行代码中，`response_model` 的类型注解是 `Author` 数据类列表；

from pydantic import BaseModel

app = FastAPI()


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


class User(BaseModel):
    username: str
    full_name: Union[str, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,
    user: User,
    importance: int = Body(gt=0),

@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(
            status_code=404, detail="Item not found, there's only a plumbus here"
        )

    context = browser.new_context(viewport={"width": 960, "height": 1080})
    page = context.new_page()
    page.goto("http://localhost:8000/docs")
    page.get_by_role("button", name="GET /items/ Read Items").click()
    page.get_by_role("button", name="Try it out").click()
    # Manually add the screenshot
    page.screenshot(path="docs/en/docs/img/tutorial/header-param-models/image01.png")

    # ---------------------