Race condition without thread locking

threads_without_lock.py

from time import sleep
import threading

counter = 10000 # dummy farmer balance in wallet

def decrease_without_thread_locking(by):
    global counter
    print(f"Initial Balance: {counter}")
    local_counter = counter
    local_counter -= by # simulate deducting the amount the farmer want to withdraw from the wallet
    sleep(1) # sleeping to simulate when it is saving the new balance to the db or performing another task like sending sms to the farmer
    counter = local_counter
    print(f"Updated balance: {counter}")


# opening multiple threads here to simulate multiple processes trying to acquire the same balance at the same time
thread_1 = threading.Thread(target=decrease_without_thread_locking, args=(500,))
thread_2 = threading.Thread(target=decrease_without_thread_locking, args=(500, ))
thread_3 = threading.Thread(target=decrease_without_thread_locking, args=(500,))
thread_4 = threading.Thread(target=decrease_without_thread_locking, args=(500,))
thread_5 = threading.Thread(target=decrease_without_thread_locking, args=(500,))
thread_6 = threading.Thread(target=decrease_without_thread_locking, args=(500,))
thread_7 = threading.Thread(target=decrease_without_thread_locking, args=(500,))


thread_1.start()
thread_2.start()
thread_3.start()
thread_4.start()
thread_5.start()
thread_6.start()
thread_7.start()


thread_1.join()
thread_2.join()
thread_3.join()
thread_4.join()
thread_5.join()
thread_6.join()
thread_7.join()