...Although if the whole application is just **crashing immediately** it probably doesn't make sense to keep restarting it forever. But in those cases, you will probably notice it during development, or at least right after deployment.

    So let's focus on the main cases, where it could crash entirely in some particular cases **in the future**, and it still makes sense to restart it.

                operation["callbacks"] = callbacks
            if route.status_code is not None:
                status_code = str(route.status_code)
            else:
                # It would probably make more sense for all response classes to have an
                # explicit default status_code, and to extract it from them, instead of
                # doing this inspection tricks, that would probably be in the future

### Tags with Enums

If you have a big application, you might end up accumulating **several tags**, and you would want to make sure you always use the **same tag** for related *path operations*.

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

```Python hl_lines="1  8-10  13  18"
{!../../../docs_src/path_operation_configuration/tutorial002b.py!}
```

You probably wouldn't want to take your crush 😍 with you to do errands at the bank 🏦.

### Burger Conclusion

In this scenario of "fast food burgers with your crush", as there is a lot of waiting 🕙, it makes a lot more sense to have a concurrent system ⏸🔀⏯.

This is the case for most of the web applications.

Many, many users, but your server is waiting 🕙 for their not-so-good connection to send their requests.

* Generate <a href="https://json-schema.org" class="external-link" target="_blank">JSON Schema</a> definitions for your model, you can also use them anywhere else you like if it makes sense for your project.
* Those schemas will be part of the generated OpenAPI schema, and used by the automatic documentation <abbr title="User Interfaces">UIs</abbr>.

## Automatic docs

    ```Python hl_lines="68-69  81"
    {!> ../../../docs_src/websockets/tutorial002.py!}
    ```

!!! info
    As this is a WebSocket it doesn't really make sense to raise an `HTTPException`, instead we raise a `WebSocketException`.

Setting options in `include_router` still makes sense in some cases, for example, to override or increase configurations from a third party router included in an app. But in a router that is part of a bigger application, it would probably make more sense to add those settings when creating the `APIRouter`.

**In `FastAPI`**

We are going to start from where we left in the previous chapter and increment it.

## About JWT

JWT means "JSON Web Tokens".

It's a standard to codify a JSON object in a long dense string without spaces. It looks like this:

```
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
```

* **Machine Learning**: Normalmente exige muita multiplicação de matrizes e vetores. Pense numa grande folha de papel com números e multiplicando todos eles juntos e ao mesmo tempo.

                and `response_model_exclude_defaults`. You probably want to use one of
                those two instead of this one, as those allow returning `None` values
                when it makes sense.

                Read more about it in the
                [FastAPI docs for Response Model - Return Type](https://fastapi.tiangolo.com/tutorial/response-model/#response_model_exclude_none).
                """