code: def stylesheet_url(path, only_path=False, cache_buster=True):
      
      filepath = String.unquoted(path).value
      if callable(config.STATIC_ROOT):
          try:
              _file, _storage = list(config.STATIC_ROOT(filepath))[0]
          except IndexError:
              filetime = None
          else:
              filetime = getmtime(_file, _storage)
          if filetime is None:
              filetime = 'NA'
      else:
          _path = os.path.join(config.STATIC_ROOT, filepath.strip('/'))
          filetime = getmtime(_path)
          if filetime is None:
              filetime = 'NA'
      BASE_URL = config.STATIC_URL
  
      url = '%s%s' % (BASE_URL, filepath)
      if cache_buster:
          url = add_cache_buster(url, filetime)
      if only_path:
          return String.unquoted(url)
      else:
          return Url.unquoted(url)
docs: Generates a path to an asset found relative to the project's css directory.
      Passing a true value as the second argument will cause the only the path to
      be returned instead of a `url()` function