How do I get child process PIDs when using ProcessPoolExecuter?

I'm using ProcessPoolExecutor context manager to run several Kafka consumers in parallel. I need to store the process IDs of the child processes so that later, I can cleanly terminate those processes. I have such code:

Class MultiProcessConsumer:    ...    def run_in_parallel(self):        parallelism_factor = 5        with ProcessPoolExecutor() as executor:            processes = [executor.submit(self.consume) for _ in range(parallelism_factor)]            # It would be nice If I could write [process.pid for process in processes] to a file here.    def consume(self):        while True:            for message in self.kafka_consumer:                do_stuff(message)

I know I can use os.get_pid() in the consume method to get PIDs. But, handling them properly (in case of constant shutting down or starting up of consumers) requires some extra work.

How would you propose that I get and store PIDs of the child processes in such a context?