docs: def _get_page_content(self, response):
          """Given a :class:`requests.Response`, return the
          :class:`xml.etree.Element` of the content `div`.
  
          :param response: a :class:`requests.Response` to parse
          :returns: the :class:`Element` of the first content `div` or `None`
          """
          document = html5lib.parse(
              response.content,
              encoding=response.encoding,
              treebuilder='etree',
              namespaceHTMLElements=False
          )
          # etree doesn't fully support XPath, so we can't just search
          # the attribute values for "content"
          divs = document.findall(
              ".//body//div[@class]")
          content_div = None
          for div in divs:
              if "content" in div.attrib['class'].split(' '):
                  content_div = div
                  break
  
          # The `Element` object is False-y when there are no subelements,
          # so compare to `None`
          if content_div is None:
              return None
          return content_div