code: def parse_path(root_dir):
      
      base_dir, last_dir, position = '', '', 0
      if root_dir:
          base_dir, last_dir = os.path.split(root_dir)
          position = -len(last_dir) if last_dir else 0
      return base_dir, last_dir, position
docs: Split path into head and last component for the completer.
      Also return position where last component starts.
      :param root_dir: str path
      :return: tuple of (string, string, int)