## Detalles Técnicos

Las versiones modernas de Python tienen soporte para **"código asíncrono"** usando algo llamado **"coroutines"**, usando la sintaxis **`async` y `await`**.

Veamos esa frase por partes en las secciones siguientes:

* **Código Asíncrono**
* **`async` y `await`**
* **Coroutines**

## Código Asíncrono

/// tip | "Dica"

Utilize a versão com `Annotated` se possível.

///

```Python hl_lines="12"
{!> ../../docs_src/dependencies/tutorial002.py!}
```

////

...ele possui os mesmos parâmetros que nosso `common_parameters` anterior:

//// tab | Python 3.10+

```Python hl_lines="8"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

  optional int32 lendablePercent = 3;

  // `borrowingLimitPercent`, if present, configures a limit on how many
  // seats this priority level can borrow from other priority levels.
  // The limit is known as this level's BorrowingConcurrencyLimit
  // (BorrowingCL) and is a limit on the total number of seats that this
  // level may borrow at any one time.
  // This field holds the ratio of that limit to the level's nominal

  optional int32 lendablePercent = 3;

  // `borrowingLimitPercent`, if present, configures a limit on how many
  // seats this priority level can borrow from other priority levels.
  // The limit is known as this level's BorrowingConcurrencyLimit
  // (BorrowingCL) and is a limit on the total number of seats that this
  // level may borrow at any one time.
  // This field holds the ratio of that limit to the level's nominal

   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6409434">Sun bug 6409434</a> is fixed.
   * It's unclear whether nulls were to be permitted or forbidden, but presumably the eventual fix
   * will be to permit them, as it seems more likely that code would depend on that behavior than on
   * the other. Thus, we say the bug is in add(), which fails to support null.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection

   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6409434">Sun bug 6409434</a> is fixed.
   * It's unclear whether nulls were to be permitted or forbidden, but presumably the eventual fix
   * will be to permit them, as it seems more likely that code would depend on that behavior than on
   * the other. Thus, we say the bug is in add(), which fails to support null.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection

Quando se refere à máquina remota, é comum chamá-la de **servidor**, mas também de **máquina**, **VM** (máquina virtual), **nó**. Todos esses termos se referem a algum tipo de máquina remota, normalmente executando Linux, onde você executa programas.

## Instale o Programa Servidor

Tristemente, no obtienes nada útil:

<img src="https://fastapi.tiangolo.com/img/python-types/image01.png">

### Añade tipos

Vamos a modificar una única línea de la versión previa.

Vamos a cambiar exactamente este fragmento, los parámetros de la función, de:

```Python
    first_name, last_name
```

a:

```Python
    first_name: str, last_name: str
```

```

Aquí la variable `app` será un instance de la clase `FastAPI`.

Este será el punto de interacción principal para crear todo tu API.

Esta `app` es la misma a la que nos referimos cuando usamos el comando de `uvicorn`:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

Use [CertificatePinner](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-certificate-pinner/) to restrict which certificates and certificate authorities are trusted. Certificate pinning increases security, but limits your server team’s abilities to update their TLS certificates. **Do not use certificate pinning without the blessing of your server’s TLS administrator!**

=== ":material-language-kotlin: Kotlin"
    ```kotlin