code: def isatty_from_env(cls, env):
      
      def str_int_bool(i):
        return i.isdigit() and bool(int(i))  # Environment variable values should always be strings.
  
      return tuple(
        str_int_bool(env.get(cls.TTY_ENV_TMPL.format(fd_id), '0')) for fd_id in STDIO_DESCRIPTORS
      )
docs: Determine whether remote file descriptors are tty capable using std nailgunned env variables.
  
      :param dict env: A dictionary representing the environment.
      :returns: A tuple of boolean values indicating istty or not for (stdin, stdout, stderr).