# 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

## URL Personalizada de OpenAPI

Para personalizar la URL de OpenAPI (o eliminarla), lee la documentación para [Tutorial - Metadatos y URLs de Documentación](../tutorial/metadata.md#openapi-url){.internal-link target=_blank}.

## URLs de Documentación de OpenAPI

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

import java.util.List;
import java.util.Map;
import java.util.Set;

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

/**
 * ResolutionGroup
 */
@Deprecated
public class ResolutionGroup extends org.apache.maven.repository.legacy.metadata.ResolutionGroup {

    public ResolutionGroup(

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

import org.apache.maven.artifact.Artifact;

/**
 * Error while retrieving repository metadata from the repository - deprecated
 */
@Deprecated
public class ArtifactMetadataRetrievalException
        extends org.apache.maven.repository.legacy.metadata.ArtifactMetadataRetrievalException {

    /**
     * @param message a message

import jakarta.validation.constraints.Size;

/**
 * Form class for handling tag operations in storage management.
 * This form represents tag data including path, name, and associated metadata.
 */
public class TagForm {

    /**
     * The file or directory path associated with this tag.
     */
    @Required
    public String path;

    /**

            throws ArtifactResolutionException {
        // Metadata cannot be found

        if (result.hasMetadataResolutionExceptions()) {
            throw result.getMetadataResolutionException(0);
        }

        // Metadata cannot be retrieved

        // Cyclic Dependency Error

        if (result.hasCircularDependencyExceptions()) {

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

/**
 * Error while installing repository metadata.
 *
 */
@Deprecated
public class RepositoryMetadataInstallationException extends Throwable {
    public RepositoryMetadataInstallationException(String message) {
        super(message);

        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

 */
package org.apache.maven.repository.legacy.resolver;

import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.metadata.ArtifactMetadataSource;
import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.resolver.ArtifactResolutionRequest;
import org.apache.maven.artifact.resolver.ArtifactResolutionResult;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.repository.legacy.metadata;

import org.apache.maven.artifact.Artifact;

/**
 * Error while retrieving repository metadata from the repository.
 *
 */
@Deprecated
public class ArtifactMetadataRetrievalException extends Exception {
    private Artifact artifact;

    /**