Parsed lxml tree (Document Object Model) of the given html.

def dom(self):
        """Parsed lxml tree (Document Object Model) of the given html."""
        try:
            dom = self._original_document.dom
            # cleaning doesn't return, just wipes in place
            html_cleaner(dom)
            return leaf_div_elements_into_paragraphs(dom)
        except ValueError:
            return None