code: def rel_links(cls, page):
      
      for match in cls.REL_RE.finditer(page):
        href, rel = match.group(0), match.group(1)
        if rel not in cls.REL_TYPES:
          continue
        href_match = cls.HREF_RE.search(href)
        if href_match:
          href = cls.href_match_to_url(href_match)
          parsed_href = urlparse(href)
          if any(parsed_href.path.endswith(ext) for ext in cls.REL_SKIP_EXTENSIONS):
            continue
          yield href
docs: return rel= links that should be scraped, skipping obviously data links.