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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 getExitCode(self, command, env={}, path=None, uid=None, gid=None, usePTY=0, childFDs=None):
 """Execute a command and get the return code of the finished process. """

        deferred = defer.Deferred()
        processProtocol = _SummaryProcessProtocol(deferred)
        self.execute(processProtocol, command, env, path, uid, gid,
                     usePTY, childFDs)
        @deferred.addCallback
        def getStdOut(tuple_):
            _stdout, _stderr, exitCode = tuple_
            return exitCode
        return deferred