How to use the mqttwarn.PeriodicThread function in mqttwarn

t.daemon = True
        t.start()

    # If the config file has a [cron] section, the key names therein are
    # functions from 'myfuncs.py' which should be invoked periodically.
    # The key's value (must be numeric!) is the period in seconds.

    if cf.has_section('cron'):
        for name, val in cf.items('cron'):
            try:
                func = load_function(name)
                cron_options = parse_cron_options(val)
                interval = cron_options['interval']
                logging.debug('Scheduling function "{name}" as periodic task ' \
                              'to run each {interval} seconds via [cron] section'.format(name=name, interval=interval))
                ptlist[name] = PeriodicThread(callback=func, period=interval, name=name, srv=srv, now=asbool(cron_options.get('now')))
                ptlist[name].start()
            except AttributeError:
                logging.error("[cron] section has function [%s] specified, but that's not defined" % name)
                continue

    while not exit_flag:
        reconnect_interval = 5

        try:
            mqttc.loop_forever()
        except socket.error:
            pass
        except:
            # FIXME: add logging with trace
            raise