## Una aplicación con callbacks { #an-app-with-callbacks }

Veamos todo esto con un ejemplo.

Imagina que desarrollas una aplicación que permite crear facturas.

Estas facturas tendrán un `id`, `title` (opcional), `customer` y `total`.

{* ../../docs_src/python_types/tutorial001_py310.py hl[2] *}

### Modifier le code { #edit-it }

C'est un programme très simple.

Mais maintenant imaginez que vous l'écriviez de zéro.

À un certain moment, vous auriez commencé la définition de la fonction, vous aviez les paramètres prêts ...

 * finalized. If this object is garbage collected earlier, the backing thread will not invoke {@code
 * finalizeReferent()} on the remaining references.
 *
 * <p>As an example of how this is used, imagine you have a class {@code MyServer} that creates a
 * {@link java.net.ServerSocket ServerSocket}, and you would like to ensure that the {@code

## Um aplicativo com callbacks { #an-app-with-callbacks }

Vamos ver tudo isso com um exemplo.

Imagine que você desenvolve um aplicativo que permite criar faturas.

Essas faturas terão um `id`, `title` (opcional), `customer` e `total`.

       * not work. (Under Android in particular, we really should check the API Level instead of
       * probing for methods....) But it's hard to imagine how reachabilityFence in particular could
       * exist but throw, so we propagate anything that's thrown, presumably an unchecked Exception
       * or Error.
       */
      throwIfUnchecked(e.getCause());

Il existe certains cas d’utilisation avec des conditions spécifiques qui pourraient bénéficier de l’ancien comportement, où le code d’arrêt des dépendances avec `yield` s’exécute avant l’envoi de la réponse.

And a `description`:

{* ../../docs_src/query_params_str_validations/tutorial008_an_py310.py hl[14] *}

## Alias parameters { #alias-parameters }

Imagine that you want the parameter to be `item-query`.

Like in:

```
http://127.0.0.1:8000/items/?item-query=foobaritems
```

But `item-query` is not a valid Python variable name.

 * finalized. If this object is garbage collected earlier, the backing thread will not invoke {@code
 * finalizeReferent()} on the remaining references.
 *
 * <p>As an example of how this is used, imagine you have a class {@code MyServer} that creates a
 * {@link java.net.ServerSocket ServerSocket}, and you would like to ensure that the {@code

///

### Include an `APIRouter` with a custom `prefix`, `tags`, `responses`, and `dependencies` { #include-an-apirouter-with-a-custom-prefix-tags-responses-and-dependencies }

Now, let's imagine your organization gave you the `app/internal/admin.py` file.

It contains an `APIRouter` with some admin *path operations* that your organization shares between several projects.

Hay algunos casos de uso con condiciones específicas que podrían beneficiarse del comportamiento antiguo de ejecutar el código de salida de dependencias con `yield` antes de enviar la response.