## Détails techniques

La classe `BackgroundTasks` provient directement de <a href="https://www.starlette.dev/background/" class="external-link" target="_blank">`starlette.background`</a>.

from typing import Optional, Union

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class OtherItem(BaseModel):
    price: int


@app.post("/items/")
def save_union_body(item: Union[OtherItem, Item]):
    return {"item": item}


client = TestClient(app)

import org.codehaus.plexus.configuration.PlexusConfiguration;

/**
 * Print warnings if deprecated core parameters are used in mojo.
 *
 * @since 3.9.1
 */
@Singleton
@Named
class DeprecatedCoreExpressionValidator extends AbstractMavenPluginParametersValidator {
    private static final HashMap<String, String> DEPRECATED_CORE_PARAMETERS;

    private static final String ARTIFACT_REPOSITORY_REASON =

from fastapi import FastAPI
from pydantic import BaseModel as BaseModelV2
from pydantic.v1 import BaseModel


class Item(BaseModel):
    name: str
    description: str | None = None
    size: float


class ItemV2(BaseModelV2):
    name: str
    description: str | None = None
    size: float


app = FastAPI()


@app.post("/items/", response_model=ItemV2)
async def create_item(item: Item):

### `pydantic-settings` installieren { #install-pydantic-settings }

Stellen Sie zunächst sicher, dass Sie Ihre [virtuelle Umgebung](../virtual-environments.md){.internal-link target=_blank} erstellt und aktiviert haben, und installieren Sie dann das Package `pydantic-settings`:

<div class="termy">

```console

import org.apache.maven.repository.Proxy;
import org.apache.maven.wagon.repository.Repository;

/**
 * This class is an abstraction of the location from/to resources can be
 * transferred.
 *
 */
@Deprecated
public class DefaultArtifactRepository extends Repository implements ArtifactRepository {
    private ArtifactRepositoryLayout layout;

    private ArtifactRepositoryPolicy snapshots;

/**
 * Holds a model along with some auxiliary information. This internal utility class assists the model builder during POM
 * processing by providing a means to transport information that cannot be (easily) extracted from the model itself.
 *
 * @deprecated use {@code org.apache.maven.api.services.ModelBuilder} instead
 */
@Deprecated(since = "4.0.0")
class ModelData {
    private final ModelSource source;

    private Model model;

import org.apache.maven.api.di.Singleton;
import org.apache.maven.cling.invoker.mvnup.UpgradeContext;

/**
 * domtrip-based orchestrator for executing different upgrade strategies.
 *
 * <p>This class provides the same functionality as StrategyOrchestrator but works
 * with domtrip-based strategies for superior formatting preservation.
 *

## Ersetzendes Aktualisieren mit `PUT` { #update-replacing-with-put }

Um einen Artikel zu aktualisieren, können Sie die <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PUT" class="external-link" target="_blank">HTTP `PUT`</a> Operation verwenden.

import org.apache.maven.model.Model;

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

    String ROLE = ModelValidator.class.getName();

    ModelValidationResult validate(Model model);