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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:
 async def stop(self, **kwargs):
 """Stop pairing process."""

        if not self._pin_code:
            raise Exception('no pin given')  # TODO: new exception

        self.service.device_credentials = \
            await self.pairing_procedure.finish_pairing(self._pin_code)