* Dem Client einen **verständlichen Fehler** anzeigen, wenn die Daten ungültig sind
* Den Parameter in der OpenAPI-Schema-*Pfadoperation* **dokumentieren** (sodass er in der **automatischen Dokumentation** angezeigt wird)

## Alternativ (alt): `Query` als Defaultwert

![Interação Swagger UI](https://fastapi.tiangolo.com/img/index/index-03-swagger-02.png)

* Documentação alternativa da API com <a href="https://github.com/Rebilly/ReDoc" class="external-link" target="_blank"><strong>ReDoc</strong></a>.

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Apenas Python moderno

This is a more advanced use case. Feel free to skip it.

///

By default, **FastAPI** will create a `server` in the OpenAPI schema with the URL for the `root_path`.

But you can also provide other alternative `servers`, for example if you want *the same* docs UI to interact with both a staging and a production environment.

   *
   * @since 21.0
   */
  public static Comparator<Boolean> falseFirst() {
    return BooleanComparator.FALSE_FIRST;
  }

  /**
   * Returns a hash code for {@code value}; obsolete alternative to {@link
   * Boolean#hashCode(boolean)}.
   *
   * @param value a primitive {@code boolean} value
   * @return a hash code for the value
   */
  @InlineMe(replacement = "Boolean.hashCode(value)")

   *
   * @since 21.0
   */
  public static Comparator<Boolean> falseFirst() {
    return BooleanComparator.FALSE_FIRST;
  }

  /**
   * Returns a hash code for {@code value}; obsolete alternative to {@link
   * Boolean#hashCode(boolean)}.
   *
   * @param value a primitive {@code boolean} value
   * @return a hash code for the value
   */
  @InlineMe(replacement = "Boolean.hashCode(value)")

Aber es ist für Sie da, wenn Sie es brauchen. 🤓

///

{* ../../docs_src/dependencies/tutorial008b_an_py39.py hl[18:22,31] *}

  @IgnoreJRERequirement
  public static <T extends @Nullable Object> Supplier<T> memoizeWithExpiration(
      Supplier<T> delegate, Duration duration) {
    checkNotNull(delegate);
    // The alternative of `duration.compareTo(Duration.ZERO) > 0` causes J2ObjC trouble.
    checkArgument(
        !duration.isNegative() && !duration.isZero(), "duration (%s) must be > 0", duration);

But it's there for you if you need it. 🤓

///

{* ../../docs_src/dependencies/tutorial008b_an_py39.py hl[18:22,31] *}

An alternative you could use to catch exceptions (and possibly also raise another `HTTPException`) is to create a [Custom Exception Handler](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank}.

  @IgnoreJRERequirement
  public static <T extends @Nullable Object> Supplier<T> memoizeWithExpiration(
      Supplier<T> delegate, Duration duration) {
    checkNotNull(delegate);
    // The alternative of `duration.compareTo(Duration.ZERO) > 0` causes J2ObjC trouble.
    checkArgument(
        !duration.isNegative() && !duration.isZero(), "duration (%s) must be > 0", duration);

Pero está ahí para ti si la necesitas. 🤓

///

{* ../../docs_src/dependencies/tutorial008b_an_py39.py hl[18:22,31] *}

Una alternativa que podrías usar para capturar excepciones (y posiblemente también lanzar otra `HTTPException`) es crear un [Manejador de Excepciones Personalizado](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank}.