from datetime import datetime
import time
import os
 
from apscheduler.schedulers.background import BackgroundScheduler
 
 
def tick():
 print('Tick! The time is: %s' % datetime.now())
 
 
if __name__ == '__main__':
 scheduler = BackgroundScheduler()
 scheduler.add_job(tick, 'interval', seconds=3)
 scheduler.start()
 print('Press Ctrl+{0} to exit'.format('Break' if os.name == 'nt' else 'C'))
 
 try:
  # This is here to simulate application activity (which keeps the main thread alive).
  while True:
   time.sleep(2)
 except (KeyboardInterrupt, SystemExit):
  scheduler.shutdown() # Not strictly necessary if daemonic mode is enabled but should be done if possible

scheduler.add_job(tick, 'interval', seconds=3)

add_job(func, trigger=None, args=None, kwargs=None, id=None, name=None, misfire_grace_time=undefined, coalesce=undefined, max_instances=undefined, next_run_time=undefined, jobstore='default', executor='default', replace_existing=False, **trigger_args)
Adds the given job to the job list and wakes up the scheduler if it's already running.
 
Any option that defaults to undefined will be replaced with the corresponding default value when the job is scheduled (which happens when the scheduler is started, or immediately if the scheduler is already running).
 
The func argument can be given either as a callable object or a textual reference in the package.module:some.object format, where the first half (separated by :) is an importable module and the second half is a reference to the callable object, relative to the module.
 
The trigger argument can either be:
the alias name of the trigger (e.g. date, interval or cron), in which case any extra keyword arguments to this method are passed on to the trigger's constructor
an instance of a trigger class

def __init__(self, run_date=None, timezone=None)

scheduler.add_job(tick, 'date', run_date='2014-11-11 14:48:00')