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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 set_exception(self, exception):
 """Sets the exception on the future."""

        if not self.is_done():
            raise TransferNotDoneError(
                'set_exception can only be called once the transfer is '
                'complete.')
        self._coordinator.set_exception(exception, override=True)