code: def _get_cached_style_urls(self, asset_url_path):
          
          try:
              cached_styles = os.listdir(self.cache_path)
          except IOError as ex:
              if ex.errno != errno.ENOENT and ex.errno != errno.ESRCH:
                  raise
              return []
          except OSError:
              return []
          return [posixpath.join(asset_url_path, style)
                  for style in cached_styles
                  if style.endswith('.css')]
docs: Gets the URLs of the cached styles.