generate CPU loading with 5 sec and close it in python 2.7

cpu_test.py

# -*- coding: utf-8 -*-                                                            
                                                                                   
import threading, sys, time                                                        
from math import pi                                                                
                                                                                   
def workload(stop_event, arg):                                                     
    # while not stop_event.wait(1):                                                
        # print ("working on %s" % arg)                                            
    while not stop_event.is_set():                                                 
        pi * pi                                                                    
    print("Stopping as you wish.")                                                 
                                                                                   
                                                                                   
def main():                                                                        
    t_stop_event = threading.Event()                                               
    t = threading.Thread(target=workload, args=(t_stop_event, "some argument")) 
    t.start()                                                                      
    time.sleep(5)                                                                  
    t_stop_event.set()                                                             
    t.join()                                                                       
                                                                                   
if __name__ == "__main__":                                                         
    main()
    
# Ref
# https://stackoverflow.com/questions/18018033/how-to-stop-a-looping-thread-in-python