docs: def get_conf_d_files(path):
      """
      Return alphabetical ordered :class:`list` of the *.conf* files
      placed in the path. *path* is a directory path.
  
      ::
  
          >>> get_conf_d_files('conf/conf.d/')
          ['conf/conf.d/10-base.conf', 'conf/conf.d/99-dev.conf']
      """
      if not os.path.isdir(path):
          raise ValueError("'%s' is not a directory" % path)
      files_mask = os.path.join(path, "*.conf")
      return [f for f in sorted(glob.glob(files_mask)) if os.path.isfile(f)]