That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

The way to describe this in OpenAPI, is to mark that field as **required**, because it will always be there.

Because of that, the JSON Schema for a model can be different depending on if it's used for **input or output**:

### Container Images

All container images are available as manifest lists and support the described
architectures. It is also possible to pull a specific architecture directly by
adding the "-$ARCH" suffix  to the container image name.

name | architectures
---- | -------------

no strings, por lo que no puedes pasarlos directamente desde código de Python.

Si necesitas usar configuraciones solo de JavaScript como esas, puedes usar uno de los métodos anteriores. Sobrescribe toda la *path operation* de Swagger UI y escribe manualmente cualquier JavaScript que necesites....

Subclass [EventListener](https://square.github.io/okhttp/3.x/okhttp/okhttp3/EventListener.html) and override methods for the events you are interested in. In a successful HTTP call with no redirects or retries the sequence of events is described by this flow.

![Events Diagram](../assets/images/******@****.***)

## Alternative Events (deprecated) { #alternative-events-deprecated }

/// warning

The recommended way to handle the *startup* and *shutdown* is using the `lifespan` parameter of the `FastAPI` app as described above. If you provide a `lifespan` parameter, `startup` and `shutdown` event handlers will no longer be called. It's all `lifespan` or all events, not both.

You can probably skip this part.

///

To distinguish from the models with all optional values for **updates** and models with required values for **creation**, you can use the ideas described in [Extra Models](extra-models.md){.internal-link target=_blank}.

## Resumo e descrição

Você pode adicionar um `summary` e uma `description`:

{* ../../docs_src/path_operation_configuration/tutorial003.py hl[20:21] *}

## Descrição do docstring

* `description`: un `str` con una breve descripción de la etiqueta. Puede tener Markdown y se mostrará en la interfaz de documentación.
* `externalDocs`: un `dict` que describe documentación externa con:
    * `description`: un `str` con una breve descripción para la documentación externa.
    * `url` (**requerido**): un `str` con la URL para la documentación externa.

### Crear metadata para etiquetas

Para distinguir entre los modelos con todos los valores opcionales para **actualizaciones** y modelos con valores requeridos para **creación**, puedes utilizar las ideas descritas en [Modelos Extra](extra-models.md){.internal-link target=_blank}.

### Container Images

All container images are available as manifest lists and support the described
architectures. It is also possible to pull a specific architecture directly by
adding the "-$ARCH" suffix  to the container image name.

name | architectures
---- | -------------