```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

Using `Optional[str]` instead of just `str` will let the editor help you detect errors where you could be assuming that a value is always a `str`, when it could actually be `None` too.

`Optional[Something]` is actually a shortcut for `Union[Something, None]`, they are equivalent.

                log.error("Multiple preauth negotiate contexts");
                return false;
            }
        }

        if ( !foundPreauth ) {
            log.error("Missing preauth negotiate context");
            return false;
        }
        if ( !foundEnc && ( caps & Smb2Constants.SMB2_GLOBAL_CAP_ENCRYPTION ) != 0 ) {
            log.error("Missing encryption negotiate context");

        this.error = true;
        this.exception = e;
        this.received = true;
        synchronized ( this ) {
            notifyAll();
        }
    }


    /**
     * {@inheritDoc}
     *
     * @see jcifs.util.transport.Response#error()
     */
    @Override
    public final void error () {
        this.error = true;
        synchronized ( this ) {

                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

}

// EncodeMsg implements msgp.Encodable
func (z BucketBandwidthReport) EncodeMsg(en *msgp.Writer) (err error) {
	// map header, size 0
	_ = z
	err = en.Append(0x80)
	if err != nil {
		return
	}
	return
}

// MarshalMsg implements msgp.Marshaler
func (z BucketBandwidthReport) MarshalMsg(b []byte) (o []byte, err error) {
	o = msgp.Require(b, z.Msgsize())
	// map header, size 0
	_ = z
	o = append(o, 0x80)
	return

    level = DeprecationLevel.ERROR,
  )
  fun setProtocols(protocols: List<Protocol>) {
    delegate.protocols = protocols
  }

  @JvmName("-deprecated_protocols")
  @Deprecated(
    message = "moved to var",
    replaceWith = ReplaceWith(expression = "protocols"),
    level = DeprecationLevel.ERROR,
  )
  fun protocols(): List<Protocol> = delegate.protocols

  fun useHttps(

	for _, testCase := range testCases {
		var flag BoolFlag
		err := (&flag).UnmarshalJSON(testCase.data)
		if !testCase.expectedErr && err != nil {
			t.Fatalf("error: expected = <nil>, got = %v", err)
		}
		if testCase.expectedErr && err == nil {
			t.Fatalf("error: expected error, got = <nil>")
		}
		if err == nil && testCase.expectedResult != flag {
			t.Fatalf("result: expected: %v, got: %v", testCase.expectedResult, flag)
		}
	}
}

- CEL authorizer checks no longer raise runtime errors. Calls to "check" will always return a decision object and the authorization error (if any) can be accessed within expressions using the new decision methods "errored" and "error". ([#118804](https://github.com/kubernetes/kubernetes/pull/118804), [@benluddy](https://github.com/benluddy)) [SIG API Machinery]

                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {

                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {