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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 prod(self, limit: int = None) -> int: """.opened This function is executed by the node each time it gets its share of CPU time from the event loop. :param limit: the number of items to be serviced in this attempt :return: total number of messages serviced by this node """

        c = 0

        if self.last_prod_started:
            self.metrics.add_event(MetricsName.LOOPER_RUN_TIME_SPENT, time.perf_counter() - self.last_prod_started)
        self.last_prod_started = time.perf_counter()

        self.quota_control.update_state({
            'request_queue_size': len(self.monitor.requestTracker.unordered())}
        )

        if self.status is not Status.stopped:
            c += await self.serviceReplicas(limit)
            c += await self.serviceNodeMsgs(limit)
            c += await self.serviceClientMsgs(limit)
            with self.metrics.measure_time(MetricsName.SERVICE_NODE_ACTIONS_TIME):
                c += self._serviceActions()
            with self.metrics.measure_time(MetricsName.SERVICE_TIMERS_TIME):
                self.timer.service()
            with self.metrics.measure_time(MetricsName.SERVICE_MONITOR_ACTIONS_TIME):
                c += self.monitor._serviceActions()
            c += await self.serviceViewChanger(limit)
            c += await self.service_observable(limit)
            c += await self.service_observer(limit)
            with self.metrics.measure_time(MetricsName.FLUSH_OUTBOXES_TIME):
                self.nodestack.flushOutBoxes()

        if self.isGoing():
            with self.metrics.measure_time(MetricsName.SERVICE_NODE_LIFECYCLE_TIME):
                self.nodestack.serviceLifecycle()
            with self.metrics.measure_time(MetricsName.SERVICE_CLIENT_STACK_TIME):
                self.clientstack.serviceClientStack()

        return c