# Body - Fields

The same way you can declare additional validation and metadata in *path operation function* parameters with `Query`, `Path` and `Body`, you can declare validation and metadata inside of Pydantic models using Pydantic's `Field`.

## Import `Field`

First, you have to import it:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}


/// warning

---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    app: metallb
  name: controller
  namespace: metallb-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    app: metallb
  name: speaker
  namespace: metallb-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  labels:
    app: metallb
  name: controller

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
message PartialObjectMetadataList {
  // Standard list metadata.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ListMeta metadata = 2;

  // items contains each of the included items.

  optional string message = 6;
}

// A list of StorageVersions.
message StorageVersionList {
  // Standard list metadata.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ListMeta metadata = 1;

  // Items holds a list of StorageVersion
  repeated StorageVersion items = 2;
}

  optional LeaseSpec spec = 2;
}

// LeaseList is a list of Lease objects.
message LeaseList {
  // Standard list metadata.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ListMeta metadata = 1;

  // items is a list of schema objects.
  repeated Lease items = 2;
}

// LeaseSpec is a specification of a Lease.

- parent POM missing (in both the repository + relative path)
- component not found

Plugins:
- plugin metadata missing
- plugin metadata retrieval problem
- plugin artifact missing
- plugin artifact retrieval problem
- plugin dependency metadata missing
- plugin dependency metadata retrieval problem
- plugin configuration problem

 * under the License.
 */
package org.apache.maven.repository.legacy.metadata;

import java.util.List;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.versioning.ArtifactVersion;

/**
 * Provides some metadata operations, like querying the remote repository for a list of versions available for an
 * artifact.
 *

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.artifact.metadata;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.maven.artifact.Artifact;

// treated as informative, best-effort, supplemental data.
message Event {
  // Standard object's metadata.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ObjectMeta metadata = 1;

  // eventTime is the time when this Event was first observed. It is required.

}

// RuntimeClassList is a list of RuntimeClass objects.
message RuntimeClassList {
  // Standard list metadata.
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
  // +optional
  optional k8s.io.apimachinery.pkg.apis.meta.v1.ListMeta metadata = 1;

  // items is a list of schema objects.
  repeated RuntimeClass items = 2;
}