code: def rename_subtitle(source, template):
      
      root = os.path.dirname(source)
      old_name = os.path.basename(source)
      old_name, ext = os.path.splitext(old_name)
      ext = ext[1:]
      info = BaseSubSearcher._parse_videoname(old_name)
      s = info['season']
      e = info['episode']
  
      _, language = os.path.splitext(old_name)
      language = language[1:]
      if language == '':
          language = 'UNKNOWN'
  
      new_name = template.format(season=s, episode=e, language=language, ext=ext)
      new_file = os.path.join(root, new_name)
      os.rename(source, new_file)
      return new_file
docs: 重命名字幕文件
      @param source: 要重命名的字幕文件
      @param template: 模板，例如：'Friends.S{season:02d}.E{episode:02d}.1080p.5.1Ch.BluRay.ReEnc-DeeJayAhmed.{}.{ext}'
      支持的变量有：season, episode, language, ext