## Using `BackgroundTasks` { #using-backgroundtasks }

First, import `BackgroundTasks` and define a parameter in your *path operation function* with a type declaration of `BackgroundTasks`:

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[1,13] *}

**FastAPI** will create the object of type `BackgroundTasks` for you and pass it as that parameter.

            /*
             * The class that getResource called upon must be from within a jar that contains the import txt file.
             *
             * Note: Even though 'jump to declaration' in IJ will show this to be the 'DefaultImportsReader' from
             * the plugin Gradle distribution, this is only true at compile time.
             *

import okhttp3.tls.internal.TlsUtil.localhost
import okio.Buffer
import org.junit.jupiter.api.AfterEach
import org.junit.jupiter.api.Disabled
import org.junit.jupiter.api.Test

/**
 * Access every declaration that is deprecated with [DeprecationLevel.ERROR]. Although new Kotlin
 * code shouldn't use these, they're necessary for clients migrating from OkHttp 3.x and this test

    return accessibleObject.getDeclaredAnnotations();
  }

  // We ought to be able to implement GenericDeclaration instead its parent AnnotatedElement.
  // That would give us this method declaration. But for some reason, implementing
  // GenericDeclaration leads to weird errors in Android tests:
  // IncompatibleClassChangeError: interface not implemented

    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

Wiederum, nur mit dieser Deklaration erhalten Sie von **FastAPI**:

* Editor-Unterstützung (Codevervollständigung, usw.), selbst für verschachtelte Modelle
* Datenkonvertierung
* Datenvalidierung
* Automatische Dokumentation

* **Facile** : Conçu pour être facile à utiliser et à apprendre. Moins de temps passé à lire la documentation.
* **Concis** : Diminue la duplication de code. De nombreuses fonctionnalités liées à la déclaration de chaque paramètre. Moins de bugs.
* **Robuste** : Obtenez un code prêt pour la production. Avec une documentation interactive automatique.

Außerdem wurde in früheren Versionen das `request`-Objekt als Teil der Schlüssel-Wert-Paare im Kontext für Jinja2 übergeben.

///

/// tip | Tipp

Durch die Deklaration von `response_class=HTMLResponse` kann die Dokumentationsoberfläche erkennen, dass die <abbr title="Response – Antwort: Daten, die der Server zum anfragenden Client zurücksendet">Response</abbr> HTML sein wird.

///

* **Easy**: Designed to be easy to use and learn. Less time reading docs.
* **Short**: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.
* **Robust**: Get production-ready code. With automatic interactive documentation.

### Basado en estándares abiertos { #based-on-open-standards }

* <a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank"><strong>OpenAPI</strong></a> para la creación de APIs, incluyendo declaraciones de <abbr title="también conocido como: endpoints, rutas">path</abbr> <abbr title="también conocido como métodos HTTP, como POST, GET, PUT, DELETE">operations</abbr>, parámetros, request bodies, seguridad, etc.

{* ../../docs_src/body/tutorial001_py310.py hl[16] *}

...y declara su tipo como el modelo que creaste, `Item`.

## Resultados { #results }

Con solo esa declaración de tipo en Python, **FastAPI** hará lo siguiente:

* Leer el body del request como JSON.
* Convertir los tipos correspondientes (si es necesario).
* Validar los datos.