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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 _process_backlogged_hosting_devices(self, context):
 """Process currently backlogged devices. Go through the currently backlogged devices and process them. For devices which are now reachable (compared to last time), we call `process_services()` passing the now reachable device's id. For devices which have passed the `hosting_device_dead_timeout` and hence presumed dead, execute a RPC to the plugin informing that. heartbeat revision res['reachable'] - hosting device went from Unknown to Active state res['revived'] - hosting device went from Dead to Active inform device manager that the hosting device is now responsive res['dead'] - hosting device went from Unknown to Dead inform device manager that the hosting device is non-responding As additional note for the revived case: Although the plugin was notified, there may be some lag before the plugin actually can reschedule it's backlogged routers. subsequent device syncs will be attempted until MAX_DEVICE_SYNC_ATTEMPTS occurs. Main process_service task will resume if sync_devices is populated. :param context: RPC context :return: None """

        driver_mgr = self.get_routing_service_helper().driver_manager
        res = self._dev_status.check_backlogged_hosting_devices(driver_mgr)
        if res['reachable']:
            self.process_services(device_ids=res['reachable'])
        if res['revived']:
            LOG.debug("Reporting revived hosting devices: %s " %
                      res['revived'])
            # trigger a sync only on the revived hosting-devices
            if self.conf.cfg_agent.enable_heartbeat is True:
                self.devmgr_rpc.report_revived_hosting_devices(
                    context, hd_ids=res['revived'])
                self.process_services(device_ids=res['revived'])
        if res['dead']:
            LOG.debug("Reporting dead hosting devices: %s", res['dead'])
            self.devmgr_rpc.report_dead_hosting_devices(context,
                                                        hd_ids=res['dead'])