code: def fetch_no_cache(self, url):
          
          try:
  
              with contextlib.closing(self.opener.open(url)) as response:
                  # InfoQ does not send a 404 but a 302 redirecting to a valid URL...
                  if response.code != 200 or response.url == INFOQ_404_URL:
                      raise DownloadError("%s not found" % url)
                  return response.read()
          except urllib.error.URLError as e:
              raise DownloadError("Failed to get %s: %s" % (url, e))
docs: Fetch the resource specified and return its content.
  
              DownloadError is raised if the resource cannot be fetched.