# Body - Fields { #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` { #import-field }

First, you have to import it:

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


/// warning

        ActionResponse result = authenticator.getResponse(SsoResponseType.METADATA);

        // Verify initial state
        assertNull(result);

        // Setup with JSON response (easier to create without LastaFlute context)
        JsonResponse<?> expectedResponse = new JsonResponse<>(new HashMap<>());
        authenticator.setResponseForType(SsoResponseType.METADATA, expectedResponse);

        // Execute

	maps.Copy(metadata, encMetadata)

	// Ensure that metadata does not contain sensitive information
	crypto.RemoveSensitiveEntries(metadata)

	if isCompressible(r.Header, object) {
		// Storing the compression metadata.
		metadata[ReservedMetadataPrefix+"compression"] = compressionAlgorithmV2
	}

	opts, err := putOptsFromReq(ctx, r, bucket, object, metadata)
	if err != nil {

	}

	// if storageClass is standard no need to save it as part of metadata.
	if userDefined[xhttp.AmzStorageClass] == storageclass.STANDARD {
		delete(userDefined, xhttp.AmzStorageClass)
	}

	// Fill all the necessary metadata.
	// Update `xl.meta` content on each disks.
	for index := range partsMetadata {
		partsMetadata[index].Metadata = userDefined
		partsMetadata[index].Size = n

	"encoding/binary"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"time"

	"github.com/cespare/xxhash/v2"
	jsoniter "github.com/json-iterator/go"
)

// XL constants.
const (
	// XL metadata file carries per object metadata.
	xlStorageFormatFileV1 = "xl.json"
)

// Valid - tells us if the format is sane by validating
// format version and erasure coding information.
func (m *xlMetaV1Object) valid() bool {

 * This enum is used to differentiate between various SSO operations,
 * such as metadata requests and logout actions.
 */
public enum SsoResponseType {
    /**
     * Indicates a request for SSO metadata, which is typically used for
     * configuration and discovery in protocols like SAML.
     */
    METADATA,

    /**
     * Indicates a request to perform a logout operation, terminating the

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

import org.apache.maven.artifact.Artifact;

/**
 * AbstractArtifactMetadata
 */
@Deprecated
public abstract class AbstractArtifactMetadata
        extends org.apache.maven.repository.legacy.metadata.AbstractArtifactMetadata
        implements org.apache.maven.artifact.metadata.ArtifactMetadata {
    protected AbstractArtifactMetadata(Artifact artifact) {

					return
				}
			}
		case "Metadata":
			var zb0003 uint32
			zb0003, err = dc.ReadArrayHeader()
			if err != nil {
				err = msgp.WrapError(err, "Metadata")
				return
			}
			if cap(z.Metadata) >= int(zb0003) {
				z.Metadata = (z.Metadata)[:zb0003]
			} else {
				z.Metadata = make([]BatchJobKV, zb0003)
			}
			for za0002 := range z.Metadata {
				err = z.Metadata[za0002].DecodeMsg(dc)

import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.repository.RepositoryRequest;
import org.apache.maven.artifact.repository.metadata.RepositoryMetadataResolutionException;
import org.apache.maven.artifact.repository.metadata.Versioning;
import org.apache.maven.artifact.resolver.ArtifactNotFoundException;
import org.apache.maven.artifact.resolver.ArtifactResolutionException;

/**

    @Override
    public void addMetadata(ArtifactMetadata metadata) {
        if (metadataMap == null) {
            metadataMap = new HashMap<>();
        }

        ArtifactMetadata m = metadataMap.get(metadata.getKey());
        if (m != null) {
            m.merge(metadata);
        } else {
            metadataMap.put(metadata.getKey(), metadata);
        }
    }

    @Override