from concurrent.futures import ThreadPoolExecutor
from concurrent.futures import as_completed
from threading import current_thread
import time, random

data = ["lab1", "lab2", "lab3"]

def modify_msg(msg):
    time.sleep(random.randint(1,5))
    return "Completed: [" + msg.title() + "] in thread " + str(current_thread())

def main():
   with ThreadPoolExecutor(max_workers = 2) as executor:
      results = executor.map(modify_msg, data)

   for result in results:
      print(result)

if __name__ == '__main__':
   main()