## Nested Models

Each attribute of a Pydantic model has a type.

But that type can itself be another Pydantic model.

So, you can declare deeply nested JSON "objects" with specific attribute names, types and validations.

All that, arbitrarily nested.

### Define a submodel

For example, we can define an `Image` model:

//// tab | Python 3.10+

/**
 * Indicates that the annotated bean has a lifespan limited to a given mojo execution,
 * which means each mojo execution will result in a different instance being injected.
 * <p>
 * The following objects will be bound to the mojo execution scope:
 *     <ul>
 *         <li>{@code org.apache.maven.api.MojoExecution}</li>
 *         <li>{@code org.apache.maven.api.Project}</li>

import org.eclipse.aether.installation.InstallationException;
import org.eclipse.aether.internal.impl.DefaultInstaller;
import org.eclipse.sisu.Priority;

import static java.util.Objects.requireNonNull;

/**
 * Maven specific installer.
 */
@Singleton
@Named
@Priority(100)
final class MavenInstaller implements Installer {

    private final DefaultInstaller installer;

    rootProject.plugins.apply(TestFilesCleanupRootPlugin::class.java)
    val globalExtension = rootProject.extensions.getByType<TestFilesCleanupBuildServiceRootExtension>()

    val projectState = objects.newInstance(TestFilesCleanupProjectState::class.java)

    globalExtension.projectStates.put(path, projectState)
    projectState.projectBuildDir = layout.buildDirectory
    projectState.projectPath = path

    if (rank == null) {
      throw new IncomparableValueException(value);
    }
    return rank;
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object instanceof ExplicitOrdering) {
      ExplicitOrdering<?> that = (ExplicitOrdering<?>) object;
      return this.rankMap.equals(that.rankMap);
    }
    return false;
  }

  @Override
  public int hashCode() {
    return rankMap.hashCode();

    if (rank == null) {
      throw new IncomparableValueException(value);
    }
    return rank;
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object instanceof ExplicitOrdering) {
      ExplicitOrdering<?> that = (ExplicitOrdering<?>) object;
      return this.rankMap.equals(that.rankMap);
    }
    return false;
  }

  @Override
  public int hashCode() {
    return rankMap.hashCode();

    }

    /** {@inheritDoc} */
    public boolean equals(Object object) {
        if (this == object) {
            return true;
        }

        if (object instanceof MojoDescriptor) {
            MojoDescriptor other = (MojoDescriptor) object;

            return Objects.equals(getPluginDescriptor(), other.getPluginDescriptor())
                    && Objects.equals(getGoal(), other.getGoal());
        }

			}
			// Asserting Object Name.
			if actualResult.Object != expectedResult.Object {
				t.Errorf("Test %d: %s: Expected Object name to be \"%s\", but instead found it to be \"%s\"", i+1, instanceType, expectedResult.Object, actualResult.Object)
			}
			// Asserting UploadID.
			if actualResult.UploadID != expectedResult.UploadID {

  /**
   * For <a href="https://tools.ietf.org/html/rfc7515">JWS or JWE objects using the Compact
   * Serialization</a>.
   *
   * @since 27.1
   */
  public static final MediaType JOSE = createConstant(APPLICATION_TYPE, "jose");

  /**
   * For <a href="https://tools.ietf.org/html/rfc7515">JWS or JWE objects using the JSON
   * Serialization</a>.
   *
   * @since 27.1
   */

		c.Assert(response.StatusCode, http.StatusOK)
		// Append all objects.
		delObjReq.Objects = append(delObjReq.Objects, ObjectToDelete{
			ObjectV: ObjectV{
				ObjectName: objName,
			},
		})
	}
	// Marshal delete request.
	deleteReqBytes, err := xml.Marshal(delObjReq)
	c.Assert(err, nil)

	// Delete list of objects.