an example of concurrent.futures.ProcessPoolExecutor for python 2.7

concurrentexample.py

import concurrent.futures
import time

def sleep_print_return(input):
    print "{} started".format(input)
    time.sleep(input % 3)
    return input

def main():
    # to observe the difference, change max_workers to 1
    with concurrent.futures.ProcessPoolExecutor(max_workers=None) as executor:
        for result in executor.map(sleep_print_return, range(25)):
            # do stuff
            print "{} finished".format(result)
            pass

if __name__ == '__main__':
    main()