I wonder if the confusion comes from the name. The HTMLParser is kind of a tokenizer more than a full HTML parser, but that's probably a detail. It doesn't create a DOM Tree which you can access, but could help you to build a DOM Tree (!= DOM Document object)

https://html.spec.whatwg.org/multipage/parsing.html#overview-of-the-parsing-model

> Implementations that do not support scripting do not have to actually create a DOM Document object, but the DOM tree in such cases is still used as the model for the rest of the specification.