```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial013_py39.py!}
```

////

//// tab | Python 3.8+

Em versões abaixo do Python 3.9, você importa `Annotated` de `typing_extensions`.

Ele já estará instalado com o **FastAPI**.

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial013.py!}
```

////

      next = (keyList == null) ? null : keyList.head;
    }

    /**
     * Constructs a new iterator over all values for the specified key starting at the specified
     * index. This constructor is optimized so that it starts at either the head or the tail,
     * depending on which is closer to the specified index. This allows adds to the tail to be done
     * in constant time.
     *
     * @throws IndexOutOfBoundsException if index is invalid

    settingsListenerQueue.shutdown()
  }

  private fun failConnection(e: IOException?) {
    close(ErrorCode.PROTOCOL_ERROR, ErrorCode.PROTOCOL_ERROR, e)
  }

  /**
   * Sends any initial frames and starts reading frames from the remote peer. This should be called
   * after [Builder.build] for all new connections.
   *
   * @param sendConnectionPreface true to send connection preface frames. This should always be true

       * Each task is retained for only as long as it is running -- so it's retained only as long as
       * it would already be retained by the underlying executor.
       *
       * If the cycle test starts reporting this cycle in the future, we should add an entry to
       * cycle_suppress_list.txt.
       */
      private final AbstractService service;

      /**

En ese caso, no tendrías que preocuparte por nada de esto. 🤷

///

### Ejemplos de Estrategias para Pasos Previos

Esto **dependerá mucho** de la forma en que **implementarás tu sistema**, y probablemente estará conectado con la forma en que inicias programas, manejas reinicios, etc.

Aquí hay algunas ideas posibles:

* Un "Contenedor de Inicio" en Kubernetes que se ejecuta antes de tu contenedor de aplicación

    assertTrue(executor.isTerminated());
    assertInterrupted();
  }

  /**
   * Wrapper around {@link Stopwatch} which also contains an "expected completion time." Creating a
   * {@code Completion} starts the underlying stopwatch.
   */
  private static final class Completion {
    final Stopwatch stopwatch;
    final long expectedCompletionWaitMillis;

    Completion(long expectedCompletionWaitMillis) {

```console
$ source .venv/Scripts/activate
```

</div>

////

Ese comando creará o modificará algunas [variables de entorno](environment-variables.md){.internal-link target=_blank} que estarán disponibles para los siguientes comandos.

Una de esas variables es la variable `PATH`.

/// tip | Consejo

```console
$ source .venv/Scripts/activate
```

</div>

////

Esse comando criará ou modificará algumas [variáveis ​​de ambiente](environment-variables.md){.internal-link target=_blank} que estarão disponíveis para os próximos comandos.

Uma dessas variáveis ​​é a variável `PATH`.

/// tip | Dica

       * Each task is retained for only as long as it is running -- so it's retained only as long as
       * it would already be retained by the underlying executor.
       *
       * If the cycle test starts reporting this cycle in the future, we should add an entry to
       * cycle_suppress_list.txt.
       */
      private final AbstractService service;

      /**

<summary>About the command <code>fastapi dev main.py</code>...</summary>

The command `fastapi dev` reads your `main.py` file, detects the **FastAPI** app in it, and starts a server using <a href="https://www.uvicorn.org" class="external-link" target="_blank">Uvicorn</a>.

By default, `fastapi dev` will start with auto-reload enabled for local development.