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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 poll(self):
 """Check if child process has terminated. Set and return returncode attribute."""

        self._returncode = self.process.poll()

        if self._returncode is not None:
            self.set_status(self.S_DONE, "status set to Done")

        return self._returncode