celery beat schedule: run task instantly when start celery beat?

Question

If I create a celery beat schedule, using timedelta(days=1), the first task will be carried out after 24 hours, quote celery beat documentation:

Answer 1

I decide I could just declare a instance of every task, and execute them at celery launch. I don't like this at all because it makes starting celery beat extremely slow (if you have slow PeriodicTask), but it does what I want.

simply add this to the end of tasks.py:

########### spawn all tasks at launch! ############
localmess = locals().values()
for obj in localmess:
    if isclass(obj):
        if obj is not PeriodicTask and issubclass(obj, PeriodicTask):
            instance = obj()
            logger.info('running {0}'.format(obj))
            try:
                instance.run()
            except:
                logger.warn('task fail: {0}'.format(obj))
                pass

######## all tasks must be decleared above! ########