Extend element instead of creating new custom element

As in the [example](https://developer.mozilla.org/en-US/docs/Web/Web_Components/Using_custom_elements)
```js
class WordCount extends HTMLParagraphElement {
...
}
customElements.define("word-count", WordCount, { extends: "p" });
```
```html
<p is="word-count">
  …
</p>
```

Is there a way to create such component via preact-custom-element?