#!/usr/bin/env python3
import threading
import time
from concurrent.futures import ThreadPoolExecutor as Pool
from timeit import default_timer as timer
 
def do_work(item):
    time.sleep(.1) # pretend to do some lengthy work.
    return threading.current_thread().name, item  # return results
 
with Pool(max_workers=4) as executor:
    # submit work items to executor (in this case, just a number).
    start = timer()
    for name, item in executor.map(do_work, range(20)):
        print("%s %s" % (name, item)) # print results
 
# "Work" took .1 seconds per task.
# 20 tasks serially would be 2 seconds.
# With 4 threads should be about .5 seconds
print('time:', timer() - start)
 

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