import threading
import time
def frotz(new_baz_value):
    class Wilma:
        baz = 42
    print(f"I am thread #{threading.get_ident()} and the initial value of my Wilma.baz is {Wilma.baz}")
    Wilma.baz = new_baz_value
    print(f"I am thread #{threading.get_ident()} and my Wilma.baz has been changed to {Wilma.baz}")

for i in range(3):
    threading.Thread(target=frotz, args=(i,)).start()
    time.sleep(0.1)

"""Result:

I am thread #17212 and the initial value of my Wilma.baz is 42
I am thread #17212 and my Wilma.baz has been changed to 0
I am thread #28744 and the initial value of my Wilma.baz is 42
I am thread #28744 and my Wilma.baz has been changed to 1
I am thread #17268 and the initial value of my Wilma.baz is 42
I am thread #17268 and my Wilma.baz has been changed to 2
"""