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Python standard library: atexit

atexit provides the two functions:

register adds a function to a list of functions to be called when the Python script terminates
unregister removes a function from this list

The registered functions are not called when

the script is killed
the script calls os._exit
a fatal internal error stops the interpreter

import atexit
import time
from datetime import datetime

def the_end():
    print('the end has come.')

atexit.register(the_end)

for i in range(10):
    time.sleep(1)
    print( 10.0 / (i-5) )

Python standard library: atexit

See also