model = ModelWithDefault(foo="foo", bar="bar")
    assert jsonable_encoder(model) == {"foo": "foo", "bar": "bar", "bla": "bla"}
    assert jsonable_encoder(model, exclude_unset=True) == {"foo": "foo", "bar": "bar"}
    assert jsonable_encoder(model, exclude_defaults=True) == {"foo": "foo"}
    assert jsonable_encoder(model, exclude_unset=True, exclude_defaults=True) == {
        "foo": "foo"
    }

    private static void assertModelIsPolymorphic(Object model) {
        assert model != null

        assert model instanceof BaseModel

        assert model instanceof ShallowChildModel
        assert ((ShallowChildModel) model).getShallowMessage() == "shallow poly from 'root'"

        assert model instanceof DeepChildModel
        assert ((DeepChildModel) model).getDeepMessage() == "deep poly from 'root'"

package gorm

import "time"

// Model a basic GoLang struct which includes the following fields: ID, CreatedAt, UpdatedAt, DeletedAt
// It may be embedded into your model or you may build your own model without it
//
//	type User struct {
//	  gorm.Model
//	}
type Model struct {
	ID        uint `gorm:"primarykey"`
	CreatedAt time.Time
	UpdatedAt time.Time
	DeletedAt DeletedAt `gorm:"index"`

package v3

import (
	"istio.io/istio/pkg/model"
)

const (
	ClusterType                = model.ClusterType
	EndpointType               = model.EndpointType
	ListenerType               = model.ListenerType
	RouteType                  = model.RouteType
	SecretType                 = model.SecretType
	ExtensionConfigurationType = model.ExtensionConfigurationType
	NameTableType              = model.NameTableType

 * limitations under the License.
 */

package org.gradle.tooling.model;

// TODO:ADAM - Deprecate
/**
 * A model that is buildable by the Tooling API. Models contain various information regarding the build.
 * Models are typically tailored to a specific domain, for example build environment or IDE.
 *
 * @since 1.0-milestone-8
 */

 * <p>
 * It is an error for a {@code @Model} rule to return {@code void} and specify a non-managed type as the first parameter.
 * It is an error for a {@code @Model} rule to return {@code void} and for the first parameter to be annotated with {@link Path}.
 * It is an error for a {@code @Model} rule to specify a managed type as the return type.

 * <h3>Creating non-managed model elements</h3>
 * <p>

package gateway

import (
	corev1 "k8s.io/api/core/v1"
	k8s "sigs.k8s.io/gateway-api/apis/v1alpha2"

	"istio.io/istio/pilot/pkg/credentials"
	"istio.io/istio/pilot/pkg/model"
	creds "istio.io/istio/pilot/pkg/model/credentials"
	"istio.io/istio/pkg/config"
	"istio.io/istio/pkg/config/schema/gvk"
	"istio.io/istio/pkg/util/sets"
)

const (
	gatewayAliasForAnnotationKey = "gateway.istio.io/alias-for"

import org.apache.maven.api.xml.XmlNode;
#foreach ( $class in $model.allClasses )
import ${packageModelV4}.${class.Name};
#end

@Generated
public class ${className} {

    public String getModelVersion(${root.name} model) {
        Objects.requireNonNull(model, "model cannot be null");

#set ( $String = $model.getClass().forName("java.lang.String") )
#set ( $Comparator = $model.getClass().forName("java.util.Comparator") )

        <field>
          <name>project</name>
          <version>1.0.0</version>
          <description>Snippets of POM xml files used to supplement the data model.</description>
          <type>DOM</type>
        </field>
      </fields>
    </class>
  </classes>

## 在文档中查看

当你查看自动化文档时，你可以检查输入模型和输出模型是否都具有自己的 JSON Schema：

<img src="https://fastapi.tiangolo.com/img/tutorial/response-model/image01.png">

并且两种模型都将在交互式 API 文档中使用：

<img src="https://fastapi.tiangolo.com/img/tutorial/response-model/image02.png">

## 响应模型编码参数

你的响应模型可以具有默认值，例如：

```Python hl_lines="11  13-14"
{!../../../docs_src/response_model/tutorial004.py!}
```