You don't even have to check if the token exists to return an error. You can be sure that if your function is executed, it will have a `str` in that token.

You can try it already in the interactive docs:

<img src="/img/tutorial/security/image03.png">

We are not verifying the validity of the token yet, but that's a start already.

    List<StringCatcher> catchers = new CopyOnWriteArrayList<>();
    List<Future<?>> futures = new ArrayList<>();
    ExecutorService executor = newFixedThreadPool(10);
    int numberOfCatchers = 10000;
    for (int i = 0; i < numberOfCatchers; i++) {
      futures.add(executor.submit(new Registrator(bus, catchers)));
    }
    for (int i = 0; i < numberOfCatchers; i++) {
      futures.get(i).get();
    }

Public\n  show(callback) {\n    if (!this._config.isVisible) {\n      execute(callback)\n      return\n    }\n\n    this._append()\n\n    const element = this._getElement()\n    if (this._config.isAnimated) {\n      reflow(element)\n    }\n\n    element.classList.add(CLASS_NAME_SHOW)\n\n    this._emulateAnimation(() => {\n      execute(callback)\n    })\n  }\n\n  hide(callback) {\n    if (!this._config.isVisible) {\n      execute(callback)\n      return\n    }\n\n    this._getElement().classList.r...

<font color="#4E9A06">INFO</font>:     Application startup complete.
</pre>
```

</div>

Es **ALTAMENTE recomendable** que escribas o copies el código, lo edites y lo ejecutes localmente.

Usarlo en tu editor es lo que realmente te muestra los beneficios de FastAPI, al ver cuán poco código tienes que escribir, todos los chequeos de tipos, autocompletado, etc.

---

## Instalar FastAPI

 * until [nextPart] returns null. After calling [nextPart] any preceding parts should not be read.
 *
 * Typical use loops over the parts in sequence:
 *
 * ```kotlin
 * val response: Response = call.execute()
 * val multipartReader = MultipartReader(response.body!!)
 *
 * multipartReader.use {
 *   while (true) {
 *     val part = multipartReader.nextPart() ?: break
 *     process(part.headers, part.body)
 *   }
 * }

        it.proceed(it.request())
      }.build()

  private fun makeRequest(client: OkHttpClient): Handshake {
    val call = client.newCall(Request(server.url("/")))
    return call.execute().use { it.handshake!! }
  }

```
./bin/spark-submit --class org.apache.spark.examples.SparkPi \
    --master yarn-client \
    --num-executors 1 \
    --driver-memory 512m \
    --executor-memory 512m \
    --executor-cores 1 \
    examples/jars/spark-examples*.jar 10
```

The job should produce an output as shown below. Note the value of pi in the output.

```

  * Contiene el `username` y `password` enviados.

{* ../../docs_src/security/tutorial006_an_py39.py hl[4,8,12] *}

Cuando intentas abrir la URL por primera vez (o haces clic en el botón "Execute" en la documentación) el navegador te pedirá tu nombre de usuario y contraseña:

<img src="/img/tutorial/security/image12.png">

## Revisa el nombre de usuario

Aquí hay un ejemplo más completo.

    * Es enthält den gesendeten `username` und das gesendete `password`.

{* ../../docs_src/security/tutorial006_an_py39.py hl[4,8,12] *}
Wenn Sie versuchen, die URL zum ersten Mal zu öffnen (oder in der Dokumentation auf den Button „Execute“ zu klicken), wird der Browser Sie nach Ihrem Benutzernamen und Passwort fragen:

<img src="/img/tutorial/security/image12.png">

## Den Benutzernamen überprüfen

Hier ist ein vollständigeres Beispiel.

    * It contains the `username` and `password` sent.

{* ../../docs_src/security/tutorial006_an_py39.py hl[4,8,12] *}

When you try to open the URL for the first time (or click the "Execute" button in the docs) the browser will ask you for your username and password:

<img src="/img/tutorial/security/image12.png">

## Check the username { #check-the-username }

Here's a more complete example.