```Python
async with lifespan(app):
    await do_stuff()
```

Quando você cria um gerenciador de contexto ou um gerenciador de contexto assíncrono como acima, o que ele faz é: antes de entrar no bloco `with`, ele executa o código antes do `yield`, e após sair do bloco `with`, ele executa o código depois do `yield`.

{* ../../docs_src/handling_errors/tutorial001_py39.py hl[1] *}

### Raise an `HTTPException` in your code { #raise-an-httpexception-in-your-code }

`HTTPException` is a normal Python exception with additional data relevant for APIs.

Because it's a Python exception, you don't `return` it, you `raise` it.

* Existem também um arquivo `app/dependencies.py`, assim como o `app/main.py`, ele é um "módulo": `app.dependencies`.
* Há um subdiretório `app/routers/` com outro arquivo `__init__.py`, então ele é um "subpacote Python": `app.routers`.
* O arquivo `app/routers/items.py` está dentro de um pacote, `app/routers/`, portanto, é um "submódulo": `app.routers.items`.
* O mesmo com `app/routers/users.py`,  ele é outro submódulo: `app.routers.users`.

Puedes ver esos esquemas porque fueron declarados con los modelos en la app.

Esa información está disponible en el **OpenAPI schema** de la app, y luego se muestra en la documentación de la API.

Y esa misma información de los modelos que está incluida en OpenAPI es lo que puede usarse para **generar el código del cliente**.

### Hey API { #hey-api }

/**
 * {@code Escaper} instances suitable for strings to be included in XML attribute values and
 * elements' text contents. When possible, avoid manual escaping by using templating systems and
 * high-level APIs that provide autoescaping. For example, consider <a
 * href="http://www.xom.nu/">XOM</a>.
 *
 * <p><b>Note:</b> Currently the escapers provided by this class do not escape any characters

It would actually be common to use Requests *inside* of a FastAPI application.

But still, FastAPI got quite some inspiration from Requests.

**Requests** is a library to *interact* with APIs (as a client), while **FastAPI** is a library to *build* APIs (as a server).

They are, more or less, at opposite ends, complementing each other.

In those cases, you can use the *path operation decorator* parameter `response_model` instead of the return type.

You can use the `response_model` parameter in any of the *path operations*:

* `@app.get()`
* `@app.post()`
* `@app.put()`
* `@app.delete()`
* etc.

{* ../../docs_src/response_model/tutorial001_py310.py hl[17,22,24:27] *}

/// note

### Eine `HTTPException` in Ihrem Code auslösen { #raise-an-httpexception-in-your-code }

`HTTPException` ist eine normale Python-Exception mit zusätzlichen Daten, die für APIs relevant sind.

Weil es eine Python-Exception ist, geben Sie sie nicht zurück (`return`), sondern lösen sie aus (`raise`).

Sie können diese Schemas sehen, da sie mit den Modellen in der App deklariert wurden.

Diese Informationen sind im **OpenAPI-Schema** der Anwendung verfügbar und werden in der API-Dokumentation angezeigt.

Diese Informationen aus den Modellen, die in OpenAPI enthalten sind, können verwendet werden, um **den Client-Code zu generieren**.

### Hey API { #hey-api }

      toolVersion = rootProject.libs.versions.checkStyle.get()
      sourceSets = listOf(project.sourceSets["main"])
    }

    // Animal Sniffer confirms we generally don't use APIs not on Java 8.
    configure<AnimalSnifferExtension> {
      annotation = "okhttp3.internal.SuppressSignatureCheck"
      sourceSets = listOf(project.sourceSets["main"])
      signatures = androidSignature + jvmSignature