docs: def auto_directory(rel_name):
      """
      if you're using py.path you make do that as:
      py.path.local(full_path).ensure_dir()
      """
      dir_name = rel_path(rel_name, check=False)
      if not os.path.exists(dir_name):
          os.makedirs(dir_name, exist_ok=True)
      return dir_name