code: def format_prefix(filename, sres):
    
    try:
      pwent = pwd.getpwuid(sres.st_uid)
      user = pwent.pw_name
    except KeyError:
      user = sres.st_uid
  
    try:
      grent = grp.getgrgid(sres.st_gid)
      group = grent.gr_name
    except KeyError:
      group = sres.st_gid
  
    return '%s %3d %10s %10s %10d %s' % (
        format_mode(sres),
        sres.st_nlink,
        user,
        group,
        sres.st_size,
        format_mtime(sres.st_mtime),
    )
docs: Prefix to a filename in the directory listing. This is to make the
    listing similar to an output of "ls -alh".