if value is None:
        if field.required:
            return None, [get_missing_field_error(loc=loc)]
        else:
            return deepcopy(field.default), []
    v_, errors_ = field.validate(value, values, loc=loc)
    if isinstance(errors_, ErrorWrapper):
        return None, [errors_]
    elif isinstance(errors_, list):
        new_errors = _regenerate_error_with_loc(errors=errors_, loc_prefix=())

  private transient Map<K, KeyList<K, V>> keyToKeyList;
  private transient int size;

  /*
   * Tracks modifications to keyToKeyList so that addition or removal of keys invalidates
   * preexisting iterators. This does *not* track simple additions and removals of values
   * that are not the first to be added or last to be removed for their key.
   */
  private transient int modCount;

	} else {
		v, ok = r.Header[xhttp.AmzContentSha256]
	}

	// Skip if no header was set.
	if !ok {
		return true
	}

	// If x-amz-content-sha256 is set and the value is not
	// 'UNSIGNED-PAYLOAD' we should validate the content sha256.
	switch v[0] {
	case unsignedPayload, unsignedPayloadTrailer:
		return true
	case emptySHA256:
		// some broken clients set empty-sha256
		// with > 0 content-length in the body,

				ClientConfig: admitv1.WebhookClientConfig{
					URL:      &remoteInjectionURL,
					CABundle: []byte("ca"),
				},
			},
		},
	}
	remoteValidationURL = "https://random.host.com/validate"
)

func TestGenerateValidatingWebhook(t *testing.T) {
	tcs := []struct {
		name           string
		istioNamespace string
		webhook        admitv1.MutatingWebhookConfiguration
		whURL          string

    public HtmlResponse index() {
        saveToken();
        return asListHtml();
    }

    @Execute
    @Secured({ ROLE })
    public HtmlResponse upload(final UploadForm form) {
        validate(form, messages -> {}, this::asListHtml);
        verifyToken(this::asListHtml);
        final String fileName = form.bulkFile.getFileName();

		return BucketRemoteArnTypeInvalid{Bucket: bucket}
	}
	clnt, err := sys.getRemoteTargetClient(tgt)
	if err != nil {
		return BucketRemoteTargetNotFound{Bucket: tgt.TargetBucket, Err: err}
	}
	// validate if target credentials are ok
	exists, err := clnt.BucketExists(ctx, tgt.TargetBucket)
	if err != nil {
		switch minio.ToErrorResponse(err).Code {
		case "NoSuchBucket":

}

func fixWhConfig(client kube.Client, whConfig *tagWebhookConfig) (*tagWebhookConfig, error) {
	if whConfig.URL != "" {
		webhookURL, err := url.Parse(whConfig.URL)
		if err == nil {
			webhookURL.Path = "/validate"
			whConfig.URL = webhookURL.String()
		}
	}

	// ValidatingWebhookConfiguration failurePolicy is managed by Istiod, so if currently we already have a webhook in cluster

							reqType, bucketName, test.objectName, err)
					}
					// Validate whether the error has occurred for the expected reason.
					if want.Code != errXML.Code {
						t.Errorf("%s, Expected to fail with error \"%s\", but received \"%s\": %q.",
							reqType, want.Code, errXML.Code, errXML.Message)
					}
					// Validate the HTTP response status code  with the expected one.
					if want.HTTPStatusCode != rec.Code {

            System.setProperties(oldProps);
        }
    }

    protected int doInvoke(C context) throws Exception {
        pushProperties(context);
        validate(context);
        prepare(context);
        configureLogging(context);
        activateLogging(context);
        helpOrVersionAndMayExit(context);
        preCommands(context);
        container(context);

```

////

//// tab | Python 3.8+

```Python hl_lines="18  23"
{!> ../../docs_src/response_model/tutorial001_01.py!}
```

////

FastAPI will use this return type to:

* **Validate** the returned data.