code: def format_mode(sres):
    
    mode = sres.st_mode
  
    root = (mode & 0o700) >> 6
    group = (mode & 0o070) >> 3
    user = (mode & 0o7)
  
    def stat_type(md):
      ''' stat type'''
      if stat.S_ISDIR(md):
        return 'd'
      elif stat.S_ISSOCK(md):
        return 's'
      else:
        return '-'
  
    def triple(md):
      ''' triple '''
      return '%c%c%c' % (
          'r' if md & 0b100 else '-',
          'w' if md & 0b010 else '-',
          'x' if md & 0b001 else '-')
  
    return ''.join([stat_type(mode), triple(root), triple(group), triple(user)])
docs: Format a line in the directory list based on the file's type and other attributes.