Sử dụng `Optional[str]` thay cho `str` sẽ cho phép trình soạn thảo giúp bạn phát hiện các lỗi mà bạn có thể gặp như một giá trị luôn là một `str`, trong khi thực tế nó rất có thể là `None`.

`Optional[Something]` là một cách viết ngắn gọn của `Union[Something, None]`, chúng là tương đương nhau.

Điều này cũng có nghĩa là trong Python 3.10, bạn có thể sử dụng `Something | None`:

//// tab | Python 3.10+

```Python hl_lines="1"

ekingTransport","inspect","prefilterOrFactory","dataTypeOrTransport","ajaxExtend","flatOptions","ajaxSettings","active","lastModified","etag","url","isLocal","protocol","processData","async","contentType","accepts","json","responseFields","converters","* text","text html","text json","text xml","ajaxSetup","settings","ajaxPrefilter","ajaxTransport","ajax","transport","cacheURL","responseHeadersString","responseHeaders","timeoutTimer","urlAnchor","fireGlobals","uncached","callbackContext","global...

			accessKey:        credentials.AccessKey,
			secretKey:        credentials.SecretKey,
			metadata: map[string]string{
				"Content-Type": "application/json",
			},
			expectedRespStatus: http.StatusOK,
		},

		// Test case - 2.
		// Test case with invalid source object.
		2: {
			bucketName:       bucketName,
			newObjectName:    "newObject1",

### API Change

- Protobuf serialization of metav1.MicroTime timestamps (used in `Lease` and `Event` API objects) has been corrected to truncate to microsecond precision, to match the documented behavior and JSON/YAML serialization. Any existing persisted data is truncated to microsecond when read from etcd. ([#111936](https://github.com/kubernetes/kubernetes/pull/111936), [@haoruan](https://github.com/haoruan)) [SIG API Machinery]

You will see something like:

```JSON
{"item_id": 5, "q": "somequery"}
```

## Interactive API docs { #interactive-api-docs }

- github.com/envoyproxy/protoc-gen-validate: [v0.9.1 → v1.0.2](https://github.com/envoyproxy/protoc-gen-validate/compare/v0.9.1...v1.0.2)
- github.com/evanphx/json-patch: [v5.6.0+incompatible → v4.12.0+incompatible](https://github.com/evanphx/json-patch/compare/v5.6.0...v4.12.0)
- github.com/fsnotify/fsnotify: [v1.6.0 → v1.7.0](https://github.com/fsnotify/fsnotify/compare/v1.6.0...v1.7.0)

    /** The key of the message: User Info */
    public static final String LABELS_USER_INFO = "{labels.userInfo}";

    /** The key of the message: JSON Response */
    public static final String LABELS_WEB_API_JSON = "{labels.webApiJson}";

    /** The key of the message: Web Crawl Config Name */

pkg encoding/json, method (*RawMessage) UnmarshalJSON([]uint8) error
pkg encoding/json, method (*SyntaxError) Error() string
pkg encoding/json, method (*UnmarshalFieldError) Error() string
pkg encoding/json, method (*UnmarshalTypeError) Error() string
pkg encoding/json, method (*UnsupportedTypeError) Error() string
pkg encoding/json, method (*UnsupportedValueError) Error() string
pkg encoding/json, type Decoder struct

### (No, really, you MUST do this before you upgrade)

Before upgrading to Kubernetes 1.11, you must keep the following in mind:

      </match>
    </magic>
  </mime-type>

  <mime-type type="application/json">
    <sub-class-of type="text/javascript"/>
    <glob pattern="*.json"/>
  </mime-type>

  <mime-type type="application/manifest+json">
    <_comment>Web Application Manifest file</_comment>
    <sub-class-of type="application/json"/>
    <glob pattern="*.webmanifest"/>
  </mime-type>