Run the pipeline.

        :param stop: Stop event

def run(self, stop):
        """ Run the pipeline.

        :param stop: Stop event
        """
        _LOGGER.info("Starting a new pipeline on group %s", self._group)
        self._group.bridge.incr_active()
        for i, stage in enumerate(self._pipe):
            self._execute_stage(i, stage, stop)
        _LOGGER.info("Finished pipeline on group %s", self._group)
        self._group.bridge.decr_active()