code: def fetchUrls(cls, url, data, urlSearch):
          
          searchUrls = []
          searches = makeSequence(urlSearch)
          for search in searches:
              for match in search.finditer(data[0]):
                  searchUrl = match.group(1)
                  if not searchUrl:
                      raise ValueError("Pattern %s matched empty URL at %s." % (search.pattern, url))
                  out.debug(u'matched URL %r with pattern %s' % (searchUrl, search.pattern))
                  searchUrls.append(normaliseURL(urljoin(data[1], searchUrl)))
              if searchUrls:
                  # do not search other links if one pattern matched
                  break
          if not searchUrls:
              patterns = [x.pattern for x in searches]
              raise ValueError("Patterns %s not found at URL %s." % (patterns, url))
          return searchUrls
docs: Search all entries for given URL pattern(s) in a HTML page.