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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 spawn(cls, executable, args, path, env, spawnProcess=None):
 """ Run an executable with some arguments in the given working directory with the given environment variables. Returns a Deferred which fires with a two-tuple of (exit status, output list) if the process terminates without timing out or being killed by a signal. Otherwise, the Deferred errbacks with either L{error.TimeoutError} if any 10 minute period passes with no events or L{ProcessDied} if it is killed by a signal. On success, the output list is of two-tuples of (file descriptor, bytes). """

        d = defer.Deferred()
        proto = cls(d, filepath.FilePath(path))
        if spawnProcess is None:
            spawnProcess = reactor.spawnProcess
        spawnProcess(
            proto,
            executable,
            [executable] + args,
            path=path,
            env=env,
            childFDs={0: 'w', 1: 'r', 2: 'r',
                      cls.BACKCHANNEL_OUT: 'r',
                      cls.BACKCHANNEL_IN: 'w'})
        return d