* `expose_headers` - Indica quaisquer cabeçalhos de resposta que devem ser disponibilizados ao navegador. O padrão é `[]`.

{* ../../docs_src/query_params_str_validations/tutorial003_an_py310.py hl[10] *}

## Agregar expresiones regulares { #add-regular-expressions }

Puedes definir una <dfn title="Una expresión regular, regex o regexp es una secuencia de caracteres que define un patrón de búsqueda para strings.">expresión regular</dfn> `pattern` que el parámetro debe coincidir:

{* ../../docs_src/query_params_str_validations/tutorial004_an_py310.py hl[11] *}

Como ejemplo, tomemos esta función:

```python
from typing import Optional


def say_hi(name: Optional[str]):
    print(f"Hey {name}!")
```

El parámetro `name` está definido como `Optional[str]`, pero **no es opcional**, no puedes llamar a la función sin el parámetro:

```Python
say_hi()  # ¡Oh, no, esto lanza un error! 😱
```

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console
// Ici, nous ne définissons pas encore la variable d'environnement
$ python main.py

// Comme nous ne l'avons pas définie, nous obtenons la valeur par défaut

Hello World from Python

// Mais si nous créons d'abord une variable d'environnement
$ export MY_NAME="Wade Wilson"

// Puis que nous relançons le programme
$ python main.py

                .optionalArg(true)
                .desc("Defines the color mode of the output. Supported are 'auto', 'always', 'never'.")
                .build());
        options.addOption(Option.builder(CACHE_ARTIFACT_NOT_FOUND)
                .longOpt("cache-artifact-not-found")
                .hasArg()
                .desc(

* **Swagger UI**: acessível em `/docs`.
    * Você pode definir sua URL com o parâmetro `docs_url`.
    * Você pode desativá-la definindo `docs_url=None`.
* **ReDoc**: acessível em `/redoc`.
    * Você pode definir sua URL com o parâmetro `redoc_url`.
    * Você pode desativá-la definindo `redoc_url=None`.

Por exemplo, para definir o Swagger UI para ser servido em `/documentation` e desativar o ReDoc:

### Feature

- Kubernetes is now built with Go 1.19.7 ([#116407](https://github.com/kubernetes/kubernetes/pull/116407), [@cpanato](https://github.com/cpanato)) [SIG Release and Testing]

But it was created before there existed Python type hints. So, to define every <dfn title="the definition of how data should be formed">schema</dfn> you need to use specific utils and classes provided by Marshmallow.

/// check | Inspired **FastAPI** to

Use code to define "schemas" that provide data types and validation, automatically.

///

///

## OAuth2 scopes and OpenAPI { #oauth2-scopes-and-openapi }

The OAuth2 specification defines "scopes" as a list of strings separated by spaces.

The content of each of these strings can have any format, but should not contain spaces.

These scopes represent "permissions".

In OpenAPI (e.g. the API docs), you can define "security schemes".

When one of these security schemes uses OAuth2, you can also declare and use scopes.

This is normally called a **webhook**.

## Webhooks steps { #webhooks-steps }

The process normally is that **you define** in your code what is the message that you will send, the **body of the request**.

You also define in some way at which **moments** your app will send those requests or events.

And **your users** define in some way (for example in a web dashboard somewhere) the **URL** where your app should send those requests.