python_cron.py

from crontab import CronTab
from datetime import datetime

cron = CronTab()
cmds = {
  'python ~/code/reminder.py': '0/30 9-18 * * *',
  '~/code/backup.sh': '0/30 9-18 * * *',
}

for cmd, cron_str in cmds.items():
    cron_job = cron.new(command=cmd)
    cron_job.setall(cron_str)

for result in cron.run_scheduler():
    current_time = datetime.now().strftime("%H:%M:%S")
    print("cron run at", current_time)