Erstellen Sie dann Klassen-Attribute mit festgelegten Werten, welches die erlaubten Werte sein werden:

{* ../../docs_src/path_params/tutorial005_py39.py hl[1,6:9] *}


/// tip | Tipp

Falls Sie sich fragen, was „AlexNet“, „ResNet“ und „LeNet“ ist, das sind Namen von <abbr title="Genau genommen, Deep-Learning-Modellarchitekturen">Modellen</abbr> für maschinelles Lernen.

///

            }
        }

        long elapsed = (System.nanoTime() - time) / 1000000;
        // Different hosts should NOT wait for each other
        assertTrue(elapsed + " should be much less than " + (waittime * numTasks), elapsed < waittime * numTasks / 2);
    }

    /**
     * Test that file:// URLs are not delayed
     */
    public void test_fileUrl_noDelay() {

因此，如果您的 API 用户（外部开发者）发送请求到您的 API：

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

使用如下 JSON 请求体：

```JSON
{
    "id": "2expen51ve",
    "customer": "Mr. Richie Rich",
    "total": "9999"
}
```

然后，您的 API 就会处理发票，并在某个点之后，发送回调请求至 `callback_url`（外部 API）：

```
https://www.external.org/events/invoices/2expen51ve
```

JSON 请求体包含如下内容：

```JSON
{

   * <p>It should be noted that using a {@code Striped<L>} with relatively few stripes, and {@code
   * bulkGet(keys)} with a relative large number of keys can cause an excessive number of shared
   * stripes (much like the birthday paradox, where much fewer than anticipated birthdays are needed
   * for a pair of them to match). Please consider carefully the implications of the number of

 * retry policies, and contextual information.
 *
 * This exception consolidates the various SMB exception types and provides:
 * - Standardized error codes
 * - Automatic retry policies
 * - Rich contextual information
 * - Error categorization
 * - Performance metrics
 */
public class SmbOperationException extends CIFSException implements Serializable {

    private static final long serialVersionUID = 1L;

   * we've chosen to instead use a signature that benefits existing users -- and is still safe.
   *
   * For convertAll, I haven't looked as closely at *how* much existing users benefit, so we should
   * keep an eye out for problems that new users encounter. Note also that convertAll could support
   * both use cases by using @PolyNull. (By contrast, we can't use @PolyNull for our superinterface

            Doc(
                """
                Configuration passed to Pydantic to define if the response data should
                exclude fields set to `None`.

                This is much simpler (less smart) than `response_model_exclude_unset`
                and `response_model_exclude_defaults`. You probably want to use one of
                those two instead of this one, as those allow returning `None` values

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

con un JSON body de:

```JSON
{
    "id": "2expen51ve",
    "customer": "Mr. Richie Rich",
    "total": "9999"
}
```

luego *tu API* procesará la factura y, en algún momento después, enviará un request de callback al `callback_url` (la *API externa*):

```

 *   }
 * };
 * LoadingCache<Key, Graph> cache = CacheBuilder.newBuilder().build(loader);
 * }
 *
 * <p>Since this example doesn't support reloading or bulk loading, it can also be specified much
 * more simply:
 *
 * {@snippet :
 * CacheLoader<Key, Graph> loader = CacheLoader.from(key -> createExpensiveGraph(key));
 * }
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible

Wenn Sie eine zweiminütige Auffrischung benötigen, wie man Python-Typen verwendet (auch wenn Sie FastAPI nicht benutzen), schauen Sie sich das kurze Tutorial an: [Einführung in Python-Typen](python-types.md){.internal-link target=_blank}.

Sie schreiben Standard-Python mit Typen:

```Python
from datetime import date

from pydantic import BaseModel