* **Einfach**: So konzipiert, dass es einfach zu benutzen und zu erlernen ist. Weniger Zeit für das Lesen der Dokumentation.
* **Kurz**: Minimieren Sie die Verdoppelung von Code. Mehrere Funktionen aus jeder Parameterdeklaration. Weniger Bugs.
* **Robust**: Erhalten Sie produktionsreifen Code. Mit automatischer, interaktiver Dokumentation.

   * the already-requested ones are in service, otherwise we might create more threads than we need.
   *
   * We use [executeCallCount] and [runCallCount] to defend against starting more threads than we
   * need. Both fields are guarded by [lock].
   */
  private var executeCallCount = 0
  private var runCallCount = 0

      License. However, in accepting such obligations, You may act only
      on Your own behalf and on Your sole responsibility, not on behalf
      of any other Contributor, and only if You agree to indemnify,
      defend, and hold each Contributor harmless for any liability
      incurred by, or claims asserted against, such Contributor by reason
      of your accepting any such warranty or additional liability.

      License. However, in accepting such obligations, You may act only
      on Your own behalf and on Your sole responsibility, not on behalf
      of any other Contributor, and only if You agree to indemnify,
      defend, and hold each Contributor harmless for any liability
      incurred by, or claims asserted against, such Contributor by reason
      of your accepting any such warranty or additional liability.

In most cases you would (and should) have a "termination proxy" handling HTTPS for you on top, this will depend on how you deploy your application, your provider might do this for you, or you might need to set it up yourself.

!!! tip

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

## Documenting the callback

The actual callback code will depend heavily on your own API app.

And it will probably vary a lot from one app to the next.

It could be just one or two lines of code, like:

```Python
callback_url = "https://example.com/api/v1/invoices/events/"

* **Fácil**: Está diseñado para ser fácil de usar y aprender. Gastando menos tiempo leyendo documentación.
* **Corto**: Minimiza la duplicación de código. Múltiples funcionalidades con cada declaración de parámetros. Menos errores.
* **Robusto**: Crea código listo para producción con documentación automática interactiva.

* Using a cloud service that would run a container image for you, etc.

### Package Requirements

You would normally have the **package requirements** for your application in some file.

It would depend mainly on the tool you use to **install** those requirements.

The most common way to do it is to have a file `requirements.txt` with the package names and their versions, one per line.

		apiErr = ErrEventNotification
	case *event.ErrInvalidARN:
		apiErr = ErrARNNotification
	case *event.ErrARNNotFound:
		apiErr = ErrARNNotification
	case *levent.ErrInvalidARN:
		apiErr = ErrLambdaARNInvalid
	case *levent.ErrARNNotFound:
		apiErr = ErrLambdaARNNotFound
	case *event.ErrUnknownRegion:
		apiErr = ErrRegionNotification
	case *event.ErrInvalidFilterName:
		apiErr = ErrFilterNameInvalid

    In that case, you wouldn't have to worry about any of this. 🤷

### Examples of Previous Steps Strategies

This will **depend heavily** on the way you **deploy your system**, and it would probably be connected to the way you start programs, handling restarts, etc.

Here are some possible ideas: