micropython/tests/misc/sys_atexit.py

# test sys.atexit() function

import sys
try:
    sys.atexit
except AttributeError:
    print('SKIP')
    raise SystemExit

some_var = None

def do_at_exit():
    print("done at exit:", some_var)

sys.atexit(do_at_exit)

some_var = "ok"
print("done before exit")