How to use the crontab.CronSlices function in crontab

def get_schedule_interval_in_seconds(self, seconds_ago=0):
        """Return the job interval in seconds or None if there is no interval

        :params seconds_ago: return an interval the job had in the past
        """
        schedule = self.get_schedule()
        if schedule is None:
            return None

        if CronSlices.is_valid(schedule):
            try:
                job_tz = pytz.timezone(self.get_schedule_time_zone())
            except (pytz.exceptions.UnknownTimeZoneError, AttributeError):
                job_tz = pytz.utc
            c = croniter(schedule, datetime.datetime.now(job_tz) - datetime.timedelta(seconds=seconds_ago))
            return c.get_next() - c.get_prev()
        else:
            try:
                _, _, interval = self.get_schedule().split('/')
                return int(float(isodate.parse_duration(interval).total_seconds()))
            except (isodate.ISO8601Error, ValueError):
                return None

elif args.mode == "schedule":
    DEFAULT_CRON = "0 * * * *"  # every hour

    if CONFIG_BACKUP_ENABLED is None or CONFIG_BACKUP_ENABLED.lower() == "false" or CONFIG_BACKUP_ENABLED.lower() == "off":
        log.info("Configuration Backup is not activated.")
        sys.exit()

    if not os.path.exists(CONFIG_BACKUP_FOLDER):
        os.makedirs(CONFIG_BACKUP_FOLDER)
    
    from crontab import CronTab, CronSlices

    cron_schedule = DEFAULT_CRON
    # env variable can also be a cron scheadule
    if CronSlices.is_valid(CONFIG_BACKUP_ENABLED):
        cron_schedule = CONFIG_BACKUP_ENABLED
    
    # Cron does not provide enviornment variables, source them manually
    environment_file = os.path.join(RESOURCE_FOLDER, "environment.sh")
    with open(environment_file, 'w') as fp:
        for env in os.environ:
            if env != "LS_COLORS":
                fp.write("export " + env + "=\"" + os.environ[env] + "\"\n")

    os.chmod(environment_file, 0o777)

    script_file_path = os.path.realpath(__file__)
    command = ". " + environment_file + "; " + sys.executable + " '" + script_file_path + "' backup> /proc/1/fd/1 2>/proc/1/fd/2"
    cron = CronTab(user=True)

    # remove all other backup tasks

'cd',
            quoted(out_dir),
            '&&',
            quoted(ARCHIVEBOX_BINARY),
            *(['add', f'"{import_path}"'] if import_path else ['update']),
            '2>&1',
            '>',
            quoted(os.path.join(LOGS_DIR, 'archivebox.log')),

        ]
        new_job = cron.new(command=' '.join(cmd), comment=CRON_COMMENT)

        if every in ('minute', 'hour', 'day', 'week', 'month', 'year'):
            set_every = getattr(new_job.every(), every)
            set_every()
        elif CronSlices.is_valid(every):
            new_job.setall(every)
        else:
            stderr('{red}[X] Got invalid timeperiod for cron task.{reset}'.format(**ANSI))
            stderr('    It must be one of minute/hour/day/week/month')
            stderr('    or a quoted cron-format schedule like:')
            stderr('        archivebox init --every=day https://example.com/some/rss/feed.xml')
            stderr('        archivebox init --every="0/5 * * * *" https://example.com/some/rss/feed.xml')
            raise SystemExit(1)

        cron = dedupe_cron_jobs(cron)
        cron.write()

        total_runs = sum(j.frequency_per_year() for j in cron)
        existing_jobs = list(cron.find_comment(CRON_COMMENT))

        print()

def check_schedule(self):
        msgs = []
        schedule = self.get_schedule()

        if schedule is not None:
            if not CronSlices.is_valid(schedule):
                try:
                    repeat, start_time, interval = schedule.split('/')  # the parts have separate validators
                except ValueError:
                    return (
                        False, (
                            'The specified schedule "%s" is neither a valid cron schedule nor a valid'
                            ' ISO 8601 schedule' % schedule
                        ),
                    )

                # an empty start time is not valid ISO8601 but Chronos accepts it: '' == current time
                if start_time == '':
                    msgs.append('The specified schedule "%s" does not contain a start time' % schedule)
                else:
                    # Check if start time contains time zone information
                    try:

"""
        Add a single event in the crontab.
        Will add a line like:
         python /path/to/kalliope.py start --brain-file /path/to/brain.yml --run-synapse ""

        E.g:
        30 7 * * * python /home/me/kalliope/kalliope.py start --brain-file /home/me/brain.yml --run-synapse  "Say-hello"
        :param period_string: crontab period
        :type period_string: str
        :param event_id:
        :type event_id: str
        :return:
        """
        my_user_cron = CronTab(user=True)
        job = my_user_cron.new(command=self.base_command+" "+str("\"" + event_id + "\""), comment=CRONTAB_COMMENT)
        if CronSlices.is_valid(period_string):
            job.setall(period_string)
            job.enable()
        else:
            raise InvalidCrontabPeriod("The crontab period %s is not valid" % period_string)
        # write the file
        my_user_cron.write()
        Utils.print_info("Synapse \"%s\" added to the crontab" % event_id)

DEFAULT_CRON = "0 * * * *"  # every hour
    
    from crontab import CronTab, CronSlices

    cron_schedule = DEFAULT_CRON

    script_file_path = os.path.realpath(__file__)
    command = sys.executable + " '" + script_file_path + "' check> /proc/1/fd/1 2>/proc/1/fd/2"

    cron = CronTab(user=True)

    # remove all other tasks
    cron.remove_all(command=command)

    job = cron.new(command=command)
    if CronSlices.is_valid(cron_schedule):
        log.info("Scheduling cron check xfdesktop task with with cron: " + cron_schedule)
        job.setall(cron_schedule)
        job.enable()
        cron.write()
    else:
        log.info("Failed to schedule check xfdesktop. Cron is not valid.")

    log.info("Running cron jobs:")
    for job in cron:
        log.info(job)

def _is_valid_crontab(crontab):
    if CronSlices.is_valid(crontab):
        return crontab

    raise argparse.ArgumentTypeError(
        'Invalid crontab.',
    )

with open(environment_file, 'w') as fp:
        for env in os.environ:
            if env != "LS_COLORS":
                fp.write("export " + env + "=\"" + os.environ[env] + "\"\n")

    os.chmod(environment_file, 0o777)

    script_file_path = os.path.realpath(__file__)
    command = ". " + environment_file + "; " + sys.executable + " '" + script_file_path + "' backup> /proc/1/fd/1 2>/proc/1/fd/2"
    cron = CronTab(user=True)

    # remove all other backup tasks
    cron.remove_all(command=command)

    job = cron.new(command=command)
    if CronSlices.is_valid(cron_schedule):
        log.info("Scheduling cron config backup task with with cron: " + cron_schedule)
        job.setall(cron_schedule)
        job.enable()
        cron.write()
    else:
        log.info("Failed to schedule config backup. Cron is not valid.")

    log.info("Running cron jobs:")
    for job in cron:
        log.info(job)