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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def isatty_from_env(cls, env):
 """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). """

    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
    )