thread.py

import threading
n = 0
def add_one():
    global n
    n += 1
    
def fun(m):
    threads = []
    for i in range(m):
        t = threading.Thread(target=add_one)
        threads.append(t)
    for t in threads:
        t.start()
    for t in threads:
        t.join()
    return n

fun(50000)