```Python hl_lines="7"
    {!> ../../../docs_src/path_params_numeric_validations/tutorial002.py!}
    ```

But keep in mind that if you use `Annotated`, you won't have this problem, it won't matter as you're not using the function parameter default values for `Query()` or `Path()`.

=== "Python 3.9+"

    ```Python hl_lines="10"

But you can disable it by setting `syntaxHighlight` to `False`:

```Python hl_lines="3"
{!../../../docs_src/configure_swagger_ui/tutorial001.py!}
```

...and then Swagger UI won't show the syntax highlighting anymore:

<img src="/img/tutorial/extending-openapi/image03.png">

## Change the Theme

This also means that if you are inside a utility function that you are calling inside of your *path operation function*, and you raise the `HTTPException` from inside of that utility function, it won't run the rest of the code in the *path operation function*, it will terminate that request right away and send the HTTP error from the `HTTPException` to the client.

The same way, you could raise an `HTTPException` or similar in the exit code, after the `yield`.

!!! tip

    This is a somewhat advanced technique, and in most of the cases you won't really need it, as you can raise exceptions (including `HTTPException`) from inside of the rest of your application code, for example, in the *path operation function*.

    But it's there for you if you need it. 🤓

    {!> ../../../docs_src/additional_status_codes/tutorial001.py!}
    ```

!!! warning
    When you return a `Response` directly, like in the example above, it will be returned directly.

    It won't be serialized with a model, etc.

    Make sure it has the data you want it to have, and that the values are valid JSON (if you are using `JSONResponse`).

!!! note "Technical Details"

```

In this case, the `startup` event handler function will initialize the items "database" (just a `dict`) with some values.

You can add more than one event handler function.

And your application won't start receiving requests until all the `startup` event handlers have completed.

### `shutdown` event

To add a function that should be run when the application is shutting down, declare it with the event `"shutdown"`:

!!! tip
    `JSONResponse` itself is a sub-class of `Response`.

And when you return a `Response`, **FastAPI** will pass it directly.

It won't do any data conversion with Pydantic models, it won't convert the contents to any type, etc.

This gives you a lot of flexibility. You can return any data type, override any data declaration or validation, etc.

```Python hl_lines="2  7  19"
{!../../../docs_src/custom_response/tutorial003.py!}
```

!!! warning
    A `Response` returned directly by your *path operation function* won't be documented in OpenAPI (for example, the `Content-Type` won't be documented) and won't be visible in the automatic interactive docs.

!!! info
    Of course, the actual `Content-Type` header, status code, etc, will come from the `Response` object you returned.

    {!> ../../../docs_src/dependencies/tutorial006.py!}
    ```

### Return values

And they can return values or not, the values won't be used.

So, you can re-use a normal dependency (that returns a value) you already use somewhere else, and even though the value won't be used, the dependency will be executed:

=== "Python 3.9+"

    ```Python hl_lines="11  16"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python
    commons: CommonQueryParams ...
    ```

...doesn't have any special meaning for **FastAPI**. FastAPI won't use it for data conversion, validation, etc. (as it is using the `Depends(CommonQueryParams)` for that).

You could actually write just:

=== "Python 3.8+"

    ```Python