The locked() method of the Lock class

# Example Python program that prints the 
# status of a Lock instance at various points of a 
# multithreaded program that updates a global counter

import threading

counter = 0

# Inherit from the threading.Thread class and implement
# a new thread subclass to update a counter
class CounterUpdate(threading.Thread):
    # The statements that form a thread are written inside
    # the run method. The run() method is overridden here
    def run(self):
        try:
            global counter
            self.l.acquire()
            print("Lock status before updating the counter:%s"%self.l.locked())            
            counter += 1
            print("Counter:%d"%counter)
        finally:
            self.l.release()
            print("Lock status while exiting finally block:%s"%self.l.locked())            
            print("==========")

    def __init__(self, counterLock):
        super().__init__()
        self.l = counterLock 
        print("Initial lock status:%s"%self.l.locked())

ctrLock = threading.Lock()

# Create n threads that update the counter
threads = []
threadCount = 2
for i in range(0, threadCount):
    t = CounterUpdate(ctrLock)
    threads.append(t)
    t.start()

# Wait for all the threads to complete 
# before exiting the main thread
for i in range(0, 10):
    t.join()

print("Value of the counter after all the threads exit:%d"%counter)