Scheduling Python Script to run every hour accurately

Question

Before I ask, Cron Jobs and Task Scheduler will be my last options, this script will be used across Windows and Linux and I'd prefer to have a coded out method of doing this than leaving this to the end user to complete.

Is there a library for Python that I can use to schedule tasks? I will need to run a function once every hour, however, over time if I run a script once every hour and use .sleep, "once every hour" will run at a different part of the hour from the previous day due to the delay inherent to executing/running the script and/or function.

What is the best way to schedule a function to run at a specific time of day (more than once) without using a Cron Job or scheduling it with Task Scheduler?

Or if this is not possible, I would like your input as well.

AP Scheduler fit my needs exactly.

Version < 3.0

import datetime
import time
from apscheduler.scheduler import Scheduler

# Start the scheduler
sched = Scheduler()
sched.daemonic = False
sched.start()

def job_function():
    print("Hello World")
    print(datetime.datetime.now())
    time.sleep(20)

# Schedules job_function to be run once each minute
sched.add_cron_job(job_function,  minute='0-59')

out:

>Hello World
>2014-03-28 09:44:00.016.492
>Hello World
>2014-03-28 09:45:00.0.14110

Version > 3.0

(From Animesh Pandey's answer below)

from apscheduler.schedulers.blocking import BlockingScheduler

sched = BlockingScheduler()

@sched.scheduled_job('interval', seconds=10)
def timed_job():
    print('This job is run every 10 seconds.')

@sched.scheduled_job('cron', day_of_week='mon-fri', hour=10)
def scheduled_job():
    print('This job is run every weekday at 10am.')

sched.configure(options_from_ini_file)
sched.start()

Answer 1

Maybe this can help: Advanced Python Scheduler

Here's a small piece of code from their documentation:

from apscheduler.schedulers.blocking import BlockingScheduler

def some_job():
    print "Decorated job"

scheduler = BlockingScheduler()
scheduler.add_job(some_job, 'interval', hours=1)
scheduler.start()