The steps involved are as follows:

1. As shown in the following code block, the MyThreadClass class has been modified, introducing the acquire() and release() methods within the run method, while the Lock() definition is outside the definition of the class itself:

import threading
import time
import os
from threading import Thread
from random import randint

# Lock Definition
threadLock = threading.Lock()

class MyThreadClass (Thread):
   def __init__(self, name, duration):
      Thread.__init__(self)
      self.name = name
      self.duration = duration
   def run(self):
      #Acquire the Lock
      threadLock.acquire() 
      print ("---> " + self.name + 
             " running, belonging to process ID "
             + str(os.getpid()) + "
")
      time.sleep(self.duration)
      print ("---> " + self.name + " over
")
      #Release the Lock
      threadLock.release()

2. The main() function has not changed with respect to the previous code sample:

def main():
    start_time = time.time()
    # Thread Creation
    thread1 = MyThreadClass("Thread#1 ", randint(1,10))
    thread2 = MyThreadClass("Thread#2 ", randint(1,10))
    thread3 = MyThreadClass("Thread#3 ", randint(1,10))
    thread4 = MyThreadClass("Thread#4 ", randint(1,10))
    thread5 = MyThreadClass("Thread#5 ", randint(1,10))
    thread6 = MyThreadClass("Thread#6 ", randint(1,10))
    thread7 = MyThreadClass("Thread#7 ", randint(1,10))
    thread8 = MyThreadClass("Thread#8 ", randint(1,10))
    thread9 = MyThreadClass("Thread#9 ", randint(1,10))

    # Thread Running
    thread1.start()
    thread2.start()
    thread3.start()
    thread4.start()
    thread5.start()
    thread6.start()
    thread7.start()
    thread8.start()
    thread9.start()

    # Thread joining
    thread1.join()
    thread2.join()
    thread3.join()
    thread4.join()
    thread5.join()
    thread6.join()
    thread7.join()
    thread8.join()
    thread9.join()

    # End 
    print("End")
    #Execution Time
    print("--- %s seconds ---" % (time.time() - start_time))

if __name__ == "__main__":
    main()