* Then it returns the **response**.

/// note | "Technical Details"

If you have dependencies with `yield`, the exit code will run *after* the middleware.

If there were any background tasks (documented later), they will run *after* all the middleware.

///

## Create a middleware

To create a middleware you use the decorator `@app.middleware("http")` on top of a function.

      }
    }

    @Override
    public CharSource asCharSource(Charset charset) {
      if (options.length == 0) {
        // If no OpenOptions were passed, delegate to Files.lines, which could have performance
        // advantages. (If OpenOptions were passed we can't, because Files.lines doesn't have an
        // overload taking OpenOptions, meaning we can't guarantee the same behavior w.r.t. things

      }
    }

    @Override
    public CharSource asCharSource(Charset charset) {
      if (options.length == 0) {
        // If no OpenOptions were passed, delegate to Files.lines, which could have performance
        // advantages. (If OpenOptions were passed we can't, because Files.lines doesn't have an
        // overload taking OpenOptions, meaning we can't guarantee the same behavior w.r.t. things

| `minio_notify_events_sent_total`               | Total number of events sent to the targets (deprecated, please use `minio_notify_target_total_events` instead)                              |

```Python hl_lines="1  7-13  19"
{!../../docs_src/dataclasses/tutorial002.py!}
```

Die Datenklasse wird automatisch in eine Pydantic-Datenklasse konvertiert.

Auf diese Weise wird deren Schema in der Benutzeroberfläche der API-Dokumentation angezeigt:

<img src="/img/tutorial/dataclasses/image01.png">

## Datenklassen in verschachtelten Datenstrukturen

Kurz:

* `100` und darüber stehen für „Information“. Diese verwenden Sie selten direkt. Responses mit diesen Statuscodes können keinen Body haben.
* **`200`** und darüber stehen für Responses, die „Successful“ („Erfolgreich“) waren. Diese verwenden Sie am häufigsten.
    * `200` ist der Default-Statuscode, welcher bedeutet, alles ist „OK“.

        findLatest("slf4j", "org.slf4j:slf4j-api:(1.7,)", versionProperties)

        // Starting with ScalaTest 3.1.0, the third party integration were moved out of the main JAR
        findLatest("scalatest", "org.scalatest:scalatest_${versionProperties["scala"]}:(3.0,)", versionProperties)

     * track the problem back to its origin. A concrete example for such a source hint can be the file path or URL from
     * which the settings were read.
     *
     * @return the hint about the source of the problem or an empty string if unknown, never {@code null}
     */
    @Nonnull
    String getSource();

    /**

        List<MavenOptions> o = options.stream().filter(Objects::nonNull).toList();
        if (o.isEmpty()) {
            throw new IllegalArgumentException("No options specified (or all were null)");
        } else if (o.size() == 1) {
            return o.get(0);
        } else {
            return new LayeredMavenOptions<>(o);
        }
    }

    protected LayeredMavenOptions(List<O> options) {

        with(standardError) {
            files.forEach {
                assertContains("API changes in file '${it.name}' should be in alphabetical order (by type and member), yet these changes were not:\n")
            }
            changes?.forEach { assertContains(it.toString()) }
            assertContains(cleanupHint)
        }
    }

    private
    fun StringWriter.assertContains(text: String) {