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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 _raise_if_error(self):
 """ Raise IOError if process is not running anymore and the exit code is nonzero. """

        retcode = self.process.poll()
        if retcode is not None and retcode != 0:
            message = self._stderr.read().strip()
            raise IOError(message)