docs: def _get_content(self, url):
          "Get HTML content"
          target_url = self._db_url + '/' + unquote(url)    # .encode('utf-8'))
          log.debug("Opening '{0}'".format(target_url))
          try:
              f = self.opener.open(target_url)
          except HTTPError as e:
              log.error("HTTP error, your session may be expired.")
              log.error(e)
              if input("Request new permanent session and retry? (y/n)") in 'yY':
                  self.request_permanent_session()
                  return self._get_content(url)
              else:
                  return None
          log.debug("Accessing '{0}'".format(target_url))
          try:
              content = f.read()
          except IncompleteRead as icread:
              log.critical(
                  "Incomplete data received from the DB, " +
                  "the data could be corrupted."
              )
              content = icread.partial
          log.debug("Got {0} bytes of data.".format(len(content)))
          return content.decode('utf-8')