# Body - Nested Models { #body-nested-models }

With **FastAPI**, you can define, validate, document, and use arbitrarily deeply nested models (thanks to Pydantic).

## List fields { #list-fields }

You can define an attribute to be a subtype. For example, a Python `list`:

{* ../../docs_src/body_nested_models/tutorial001_py310.py hl[12] *}

This will make `tags` be a list, although it doesn't declare the type of the elements of the list.

standard = [
    "fastapi-cli[standard] >=0.0.8",
    # For the test client
    "httpx >=0.23.0,<1.0.0",
    # For templates
    "jinja2 >=3.1.5",
    # For forms and file uploads
    "python-multipart >=0.0.18",
    # To validate email fields
    "email-validator >=2.0.0",
    # Uvicorn with uvloop
    "uvicorn[standard] >=0.12.0",
    # # Settings management
    "pydantic-settings >=2.0.0",
    # # Extra Pydantic data types

 * limitations under the License.
 */
package okhttp3.testing

import okhttp3.internal.platform.Platform
import org.junit.jupiter.api.Test
import org.junit.jupiter.api.extension.RegisterExtension

/**
 * Validates which environment is used by the IDE.
 */
class PlatformRuleTest {
  @RegisterExtension @JvmField
  val platform = PlatformRule()

  @Test
  fun testMode() {
    println(PlatformRule.getPlatformSystemProperty())

/**
 * Checks the model for missing or invalid values.
 *
 */
@Deprecated
public interface ModelValidator {

    String ROLE = ModelValidator.class.getName();

    ModelValidationResult validate(Model model);

// values of maximally occurring errors validated against readQuorum.
func reduceReadQuorumErrs(ctx context.Context, errs []error, ignoredErrs []error, readQuorum int) (maxErr error) {
	return reduceQuorumErrs(ctx, errs, ignoredErrs, readQuorum, errErasureReadQuorum)
}

// reduceWriteQuorumErrs behaves like reduceErrs but only for returning
// values of maximally occurring errors validated against writeQuorum.

}
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
$webclient.DownloadFile($distributionUrl, "$TMP_DOWNLOAD_DIR/$distributionUrlName") | Out-Null

# If specified, validate the SHA-256 sum of the Maven distribution zip file
$distributionSha256Sum = (Get-Content -Raw "$scriptDir/.mvn/wrapper/maven-wrapper.properties" | ConvertFrom-StringData).distributionSha256Sum
if ($distributionSha256Sum) {

		kafkaArgs.SASL.Password = env.Get(saslPasswordEnv, kv.Get(target.KafkaSASLPassword))
		kafkaArgs.SASL.Mechanism = env.Get(saslMechanismEnv, kv.Get(target.KafkaSASLMechanism))

		if err = kafkaArgs.Validate(); err != nil {
			return nil, err
		}

		kafkaTargets[k] = kafkaArgs
	}

	return kafkaTargets, nil
}

// DefaultMQTTKVS - default MQTT config
var (
	DefaultMQTTKVS = config.KVS{

	}
}

// RetentionDate is a embedded type containing time.Time to unmarshal
// Date in Retention
type RetentionDate struct {
	time.Time
}

// UnmarshalXML parses date from Retention and validates date format
func (rDate *RetentionDate) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
	var dateStr string
	err := d.DecodeElement(&dateStr, &startElement)
	if err != nil {
		return err
	}

     * @return HTML response for the web config edit form
     */
    @Execute
    @Secured({ ROLE })
    public HtmlResponse edit(final EditForm form) {
        validate(form, messages -> {}, this::asListHtml);
        final String id = form.id;
        webConfigService.getWebConfig(id).ifPresent(entity -> {
            copyBeanToBean(entity, form, copyOp -> {

import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.stream.StreamSupport;

/**
 * Incremental task to validate that the API names in set of JSON files do not contain
 * programming language keywords.
 * <p>
 * The keywords are defined in a JSON file, although it's worth noting that what is and isn't a