* 以 JSON 形式读取请求体
* （在必要时）把请求体转换为对应的类型
* 校验数据：
    * 数据无效时返回错误信息，并指出错误数据的确切位置和内容
* 把接收的数据赋值给参数 `item`
    * 把函数中请求体参数的类型声明为 `Item`，还能获得代码补全等编辑器支持
* 为模型生成 <a href="https://json-schema.org" class="external-link" target="_blank">JSON Schema</a>，在项目中所需的位置使用
* 这些概图是 OpenAPI 概图的部件，用于 API 文档 <abbr title="用户界面">UI</abbr>

## API 文档

Pydantic 模型的 JSON 概图是 OpenAPI 生成的概图部件，可在 API 文档中显示：

 */
package okhttp3

import okio.IOException

/**
 * Protocols that OkHttp implements for [ALPN][ietf_alpn] selection.
 *
 * ## Protocol vs Scheme
 *
 * Despite its name, [java.net.URL.getProtocol] returns the [scheme][java.net.URI.getScheme] (http,
 * https, etc.) of the URL, not the protocol (http/1.1, spdy/3.1, etc.). OkHttp uses the word
 * *protocol* to identify how HTTP messages are framed.
 *

///

It will:

* Return that status code in the response.
* Document it as such in the OpenAPI schema (and so, in the user interfaces):

<img src="/img/tutorial/response-status-code/image01.png">

/// note

Some response codes (see the next section) indicate that the response does not have a body.

func (n NATSArgs) connectStan() (stan.Conn, error) {
	scheme := "nats"
	if n.Secure {
		scheme = "tls"
	}

	var addressURL string
	//nolint:gocritic
	if n.Username != "" && n.Password != "" {
		addressURL = scheme + "://" + n.Username + ":" + n.Password + "@" + n.Address.String()
	} else if n.Token != "" {
		addressURL = scheme + "://" + n.Token + "@" + n.Address.String()
	} else {

    * **Стандартизированный**: Основан на открытых стандартах API (<a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank">OpenAPI</a> и <a href="https://json-schema.org/" class="external-link" target="_blank">JSON Schema</a>) и полностью совместим с ними.

#                                                     Tomcat
#                                                     ------
tomcat.URIEncoding = UTF-8
tomcat.useBodyEncodingForURI = true
#tomcat.secure=false
#tomcat.scheme=http
#tomcat.bindAddress=127.0.0.1
#tomcat.proxyPort=

		return StorageClass{}, config.ErrStorageClassValue(nil).Msg("Too few sections in " + storageClassEnv)
	}

	// only allowed scheme is "EC"
	if s[0] != schemePrefix {
		return StorageClass{}, config.ErrStorageClassValue(nil).Msg("Unsupported scheme " + s[0] + ". Supported scheme is EC")
	}

	// Number of parity drives should be integer
	parityDrives, err := strconv.Atoi(s[1])
	if err != nil {

    email: Union[str, None] = None
    full_name: Union[str, None] = None
    disabled: Union[bool, None] = None


class UserInDB(User):
    hashed_password: str


pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl="token",
    scopes={"me": "Read information about the current user.", "items": "Read items."},
)

app = FastAPI()

        * Nas respostas, o `set` será convertido para uma `list`.
        * O esquema gerado vai especificar que os valores do `set` são unicos (usando o `uniqueItems` do JSON Schema).
* `bytes`:
    * O `bytes` padrão do Python.
    * Em requisições e respostas será representado como uma `str`.
    * O esquema gerado vai especificar que é uma `str` com o "formato" `binary`.
* `Decimal`:

import "k8s.io/api/core/v1/generated.proto";
import "k8s.io/apimachinery/pkg/apis/meta/v1/generated.proto";
import "k8s.io/apimachinery/pkg/runtime/generated.proto";
import "k8s.io/apimachinery/pkg/runtime/schema/generated.proto";

// Package-wide variables from generator "generated".
option go_package = "k8s.io/api/scheduling/v1beta1";