///

## Nützliche Standards, alternative Dokumentation { #standards-based-benefits-alternative-documentation }

Und weil das generierte Schema vom <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md" class="external-link" target="_blank">OpenAPI</a>-Standard kommt, gibt es viele kompatible Tools.

The `lifespan` parameter of the `FastAPI` app takes an **async context manager**, so we can pass our new `lifespan` async context manager to it.

{* ../../docs_src/events/tutorial003_py39.py hl[22] *}

## Alternative Events (deprecated) { #alternative-events-deprecated }

/// warning

///

## Standards-based benefits, alternative documentation { #standards-based-benefits-alternative-documentation }

And because the generated schema is from the <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md" class="external-link" target="_blank">OpenAPI</a> standard, there are many compatible tools.

 * different signatures.
 */
@GwtCompatible
@J2ktIncompatible // Super-sourced
abstract class GwtFuturesCatchingSpecialization {
  /*
   * This server copy of the class is empty. The corresponding GWT copy contains alternative
   * versions of catching() and catchingAsync() with slightly different signatures from the ones
   * found in Futures.java.
   */

@J2ktIncompatible // Super-sourced
abstract class GwtFluentFutureCatchingSpecialization<V extends @Nullable Object>
    extends AbstractFuture<V> {
  /*
   * This server copy of the class is empty. The corresponding GWT copy contains alternative
   * versions of catching() and catchingAsync() with slightly different signatures from the ones
   * found in FluentFuture.java.
   */

{* ../../docs_src/events/tutorial003_py39.py hl[22] *}

## Alternative Events (<abbr title="veraltet, obsolet: Es soll nicht mehr verwendet werden">deprecatet</abbr>) { #alternative-events-deprecated }

/// warning | Achtung

        failover.handleFailure(failedChannel, error);

        // Verify pending operations were cleared from failed channel
        assertEquals(0, failedChannel.getRequestsPending());

        // Verify alternative channel was selected and operation added
        verify(mockLoadBalancer).selectChannel(mockOperation);
        verify(alternativeChannel).addPendingOperation(mockOperation);
    }

    @Test

![Swagger UI](https://fastapi.tiangolo.com/img/index/index-01-swagger-ui-simple.png)

### Alternative API docs { #alternative-api-docs }

And now, go to <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>.

You will see the alternative automatic documentation (provided by <a href="https://github.com/Rebilly/ReDoc" class="external-link" target="_blank">ReDoc</a>):

 * different signatures.
 */
@GwtCompatible
@J2ktIncompatible // Super-sourced
abstract class GwtFuturesCatchingSpecialization {
  /*
   * This server copy of the class is empty. The corresponding GWT copy contains alternative
   * versions of catching() and catchingAsync() with slightly different signatures from the ones
   * found in Futures.java.
   */

![Swagger UI](https://fastapi.tiangolo.com/img/index/index-01-swagger-ui-simple.png)

### Alternative API-Dokumentation { #alternative-api-docs }

Und jetzt gehen Sie auf <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>.