{!> ../../docs_src/body_nested_models/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

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

////

这将使 `tags` 成为一个由元素组成的列表。不过它没有声明每个元素的类型。

## 具有子类型的 List 字段

但是 Python 有一种特定的方法来声明具有子类型的列表：

### 从 typing 导入 `List`

首先，从 Python 的标准库 `typing` 模块中导入 `List`：

```Python hl_lines="1"

	// Validates if Versioning with no excluded prefixes omits
	// ExcludedPrefixes tags
	v := Versioning{
		Status: Enabled,
	}
	buf, err := xml.Marshal(v)
	if err != nil {
		t.Fatalf("Failed to marshal %v: %v", v, err)
	}

	str := string(buf)
	if strings.Contains(str, "ExcludedPrefixes") {
		t.Fatalf("XML shouldn't contain ExcludedPrefixes tag - %s", str)
	}
}

func TestVersioningZero(t *testing.T) {

    assertThat(CertificateAdapters.extension.fromDer(bytes))
      .isEqualTo(extension)
  }

  /** Tags larger than 30 are a special case. */
  @Test fun `large tag`() {
    val bytes = "df83fb6800".decodeHex()

    val adapter = Adapters.NULL.withTag(tagClass = DerHeader.TAG_CLASS_PRIVATE, tag = 65_000L)
    assertThat(adapter.toDer(null)).isEqualTo(bytes)
    assertThat(adapter.fromDer(bytes)).isNull()
  }

            Doc(
                """
                A list of tags used by OpenAPI, these are the same `tags` you can set
                in the *path operations*, like:

                * `@app.get("/users/", tags=["users"])`
                * `@app.get("/items/", tags=["items"])`

                The order of the tags can be used to specify the order shown in

                                    "required": ["name", "tags"],
                                    "type": "object",
                                    "properties": {
                                        "name": {"title": "Name", "type": "string"},
                                        "tags": {
                                            "title": "Tags",
                                            "type": "array",

from enum import Enum

from fastapi import FastAPI

app = FastAPI()


class Tags(Enum):
    items = "items"
    users = "users"


@app.get("/items/", tags=[Tags.items])
async def get_items():
    return ["Portal gun", "Plumbus"]


@app.get("/users/", tags=[Tags.users])
async def read_users():

<%@taglib prefix="c" uri="jakarta.tags.core"%><%--
 --%><%@taglib prefix="fmt" uri="jakarta.tags.fmt"%><%--
 --%><%@taglib prefix="fn" uri="jakarta.tags.functions" %><%--
 --%><%@taglib prefix="la" uri="http://lastaflute.org/latags" %><%--
 --%><%@taglib prefix="f" uri="http://lastaflute.org/functions" %><%--
 --%><%@taglib prefix="fe" uri="fess.tags.functions" %><%--

    webhooks: Optional[Dict[str, Union[PathItem, Reference]]] = None
    components: Optional[Components] = None
    security: Optional[List[Dict[str, List[str]]]] = None
    tags: Optional[List[Tag]] = None
    externalDocs: Optional[ExternalDocumentation] = None


_model_rebuild(Schema)
_model_rebuild(Operation)

    price: float
    tax: Union[float, None] = None
    tags: set[str] = set()


@app.post("/items/", response_model=Item, tags=["items"])
async def create_item(item: Item):
    return item


@app.get("/items/", tags=["items"])
async def read_items():
    return [{"name": "Foo", "price": 42}]


@app.get("/users/", tags=["users"])
async def read_users():

    return f"{route.tags[0]}-{route.name}"


app = FastAPI(generate_unique_id_function=custom_generate_unique_id)


class Item(BaseModel):
    name: str
    price: float


class ResponseMessage(BaseModel):
    message: str


class User(BaseModel):
    username: str
    email: str


@app.post("/items/", response_model=ResponseMessage, tags=["items"])