reap_workers.py

class PoolManager:  # already existing class

    def start(self):
        self.init_signals()  # added by me
        self.worker_manager.create_workers()

# all below added by me
    def init_signals(self):
        if hasattr(signal, 'SIGCHLD'):
            signal.signal(signal.SIGCHLD, handle_chld)


def handle_chld(signum, frame):
    reap_workers()


def reap_workers():
    try:
        while True:
            wpid, status = os.waitpid(-1, os.WNOHANG)
            if not wpid:
                break
    except OSError as e:
        if e.errno != errno.ECHILD:
            raise e