Cell a = as[i];
        if (a != null) sum += a.value;
      }
    }
    return sum;
  }

  /**
   * Resets variables maintaining the sum to zero. This method may be a useful alternative to
   * creating a new adder, but is only effective if there are no concurrent updates. Because this
   * method is intrinsically racy, it should only be used when it is known that no threads are
   * concurrently updating.

    checkHelperVersion(NO_UNSAFE, "AtomicReferenceFieldUpdaterAtomicHelper");
    checkHelperVersion(NO_ATOMIC_REFERENCE_FIELD_UPDATER, "SynchronizedHelper");

    // Then, run the actual tests under each alternative classloader:

    /*
     * Under Java 8, there is no need to test the no-VarHandle case here: It's already tested by the
     * main AbstractFutureTest, which uses the default AtomicHelper, which we verified above to be

Sie wird direkt in FastAPI importiert/inkludiert, sodass Sie sie von `fastapi` importieren können und vermeiden, versehentlich das alternative `BackgroundTask` (ohne das `s` am Ende) von `starlette.background` zu importieren.

```

////

//// tab | Python 3.9+

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009_py39.py!}
```

////

//// tab | Python 3.9+ Alternative

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009b_py39.py!}
```

////

#### `Union` oder `Optional` verwenden? { #using-union-or-optional }

* Show a **clear error** for the client when the data is not valid
* **Document** the parameter in the OpenAPI schema *path operation* (so it will show up in the **automatic docs UI**)

## Alternative (old): `Query` as the default value { #alternative-old-query-as-the-default-value }

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

## Eventos alternativos (descontinuados) { #alternative-events-deprecated }

/// warning | Atenção

* Den Parameter in der OpenAPI-Schema-*Pfadoperation* **dokumentieren** (sodass er in der **automatischen Dokumentation** angezeigt wird)

## Alternative (alt): `Query` als Defaultwert { #alternative-old-query-as-the-default-value }

    assertThat(okHttpCertificate.tbsCertificate.validity).isEqualTo(Validity(-1000L, 2000L))
    assertThat(okHttpCertificate.tbsCertificate.serialNumber).isEqualTo(BigInteger("17"))
  }

  @Test
  fun `missing subject alternative names`() {
    val certificate =
      HeldCertificate
        .Builder()
        .certificateAuthority(3)
        .commonName("Jurassic Park")
        .organizationalUnit("Gene Research")

 * lifecycle phase. Standard lifecycles use plugin execution {@code <phase>} or mojo default lifecycle phase to
 * calculate the execution plan, but custom lifecycles can use alternative mapping strategies.
 */
@Named(DefaultLifecycleMappingDelegate.HINT)
@Singleton
public class DefaultLifecycleMappingDelegate implements LifecycleMappingDelegate {
    public static final String HINT = "default";

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

## Eventos Alternativos (obsoleto) { #alternative-events-deprecated }

/// warning | Advertencia