**FastAPI** is all based on Pydantic.

You will see a lot more of all this in practice in the [Tutorial - User Guide](tutorial/index.md){.internal-link target=_blank}.

!!! tip

The idea is for the **FastAPI** community to be kind and welcoming. At the same time, don't accept bullying or disrespectful behavior towards others. We have to take care of each other.

---

Here's how to help others with questions (in discussions or issues):

### Understand the question

    ```Python hl_lines="9"
    {!> ../../../docs_src/query_params_str_validations/tutorial006c.py!}
    ```

!!! tip

By returning the result of calling `generate_html_response()`, you are already returning a `Response` that will override the default **FastAPI** behavior.

But as you passed the `HTMLResponse` in the `response_class` too, **FastAPI** will know how to document it in OpenAPI and the interactive docs as HTML with `text/html`:

<img src="/img/tutorial/custom-response/image01.png">

This was changed in version 0.110.0 to fix unhandled memory consumption from forwarded exceptions without a handler (internal server errors), and to make it consistent with the behavior of regular Python code.

### Background Tasks and Dependencies with `yield`, Technical Details