docs: def secret_file(filename):
      """Will check the permissions of things which really
      should be secret files"""
      filestat = os.stat(abspath(filename))
      if stat.S_ISREG(filestat.st_mode) == 0 and \
         stat.S_ISLNK(filestat.st_mode) == 0:
          e_msg = "Secret file %s must be a real file or symlink" % filename
          raise aomi.exceptions.AomiFile(e_msg)
  
      if platform.system() != "Windows":
          if filestat.st_mode & stat.S_IROTH or \
             filestat.st_mode & stat.S_IWOTH or \
             filestat.st_mode & stat.S_IWGRP:
              e_msg = "Secret file %s has too loose permissions" % filename
              raise aomi.exceptions.AomiFile(e_msg)