Searches for `output` regex within HTML page. kwargs are passed to BeautifulSoup's find function to filter for tags.

def content(self, output=None, str_output=None, **kwargs):
        """Searches for `output` regex within HTML page. kwargs are passed to BeautifulSoup's find function to filter for tags."""
        if self.response.mimetype != "text/html":
            raise Failure(_("expected request to return HTML, but it returned {}").format(
                self.response.mimetype))

        # TODO: Remove once beautiful soup updates to accomodate python 3.7
        with warnings.catch_warnings():
            warnings.filterwarnings("ignore", category=DeprecationWarning)
            content = BeautifulSoup(self.response.data, "html.parser")

        return self._search_page(
            output,
            str_output,
            content,
            lambda regex, content: any(regex.search(str(tag)) for tag in content.find_all(**kwargs)))