def METHOD_NAME(self):
    """
    Download and rank the mirror list.
    """
    log.info('Downloading the Sage mirror list')
    try:
        with contextlib.closing(urllib.urlopen(self.URL)) as f:
            mirror_list = f.read().decode("ascii")
    except IOError:
        log.critical('Downloading the mirror list failed, using cached version')
    else:
        self.mirrors = self._load(mirror_list)
        self._rank_mirrors()
        self._save()