python threading event.wait() using same object in multiple threads

Question

where is the documentation for the python3 threading library's event.wait() method that explains how 1 event can be used multiple times in different threads?

the example below shows the same event can be used in multiple threads, each with a different wait() duration, probably because each has its own lock under the hood.

But this functionality is not documented in an obvious way, on the threading page.

this works great but it's not clear why it works or if this will continue to work in future python versions.

are there ways this could bonk unexpectedly?

can an inherited event work properly in multiple classes as long as it's used in separate threads?

import logging
import threading
import time

logging.basicConfig(level=logging.DEBUG,
                    format='[%(levelname)s] (%(threadName)-10s) %(message)s',)

def worker(i,dt,e):
    tStart=time.time()
    e.wait(dt)
    logging.debug('{0} tried to wait {1} seconds but really waited {2}'.format(i,dt, time.time()-tStart ))


e = threading.Event()

maxThreads=10
for i in range(maxThreads):
    dt=1+i # (s)
    w = threading.Thread(target=worker, args=(i,dt,e))
    w.start()

output:

[DEBUG] (Thread-1  ) 0 tried to wait 1 seconds but really waited 1.0003676414489746
[DEBUG] (Thread-2  ) 1 tried to wait 2 seconds but really waited 2.00034761428833
[DEBUG] (Thread-3  ) 2 tried to wait 3 seconds but really waited 3.0001776218414307
[DEBUG] (Thread-4  ) 3 tried to wait 4 seconds but really waited 4.000180244445801
[DEBUG] (Thread-5  ) 4 tried to wait 5 seconds but really waited 5.000337362289429
[DEBUG] (Thread-6  ) 5 tried to wait 6 seconds but really waited 6.000308990478516
[DEBUG] (Thread-7  ) 6 tried to wait 7 seconds but really waited 7.000143051147461
[DEBUG] (Thread-8  ) 7 tried to wait 8 seconds but really waited 8.000152826309204
[DEBUG] (Thread-9  ) 8 tried to wait 9 seconds but really waited 9.00012469291687
[DEBUG] (Thread-10 ) 9 tried to wait 10 seconds but really waited 10.000144481658936

Answer 1

Since e is threading Event, You are declaring it locally for each thread (all the 10 threads are excecated almost parallelly). You can check it here:

import logging
import threading
import time

logging.basicConfig(level=logging.DEBUG,
                    format='[%(levelname)s] (%(threadName)s) %(message)s',)

def worker(i,dt,e):
    tStart=time.time()
    logging.info('Program will wait for {} time while trying to print the change from {} to {}'.format(dt,i,dt))
    e.wait(dt)
    logging.debug('{0} tried to wait {1} seconds but really waited {2}'.format(i,dt, time.time()-tStart ))


e = threading.Event()

maxThreads=10
for i in range(maxThreads):
    dt=1+i # (s)
    w = threading.Thread(target=worker, args=(i,dt,e))
    w.start()

It's not the locking, its just about the value passed into the thread target