13.4. Termination Functions
The atexit module lets you register termination functions
(i.e., functions to be called at program termination:
"last in, first out"). Termination functions are similar to clean-up handlers established by try/finally. However, termination functions are globally registered and get called at the end of the whole program, while clean-up handlers are established lexically and get called at the end of a specific try clause. Both termination functions and clean-up handlers are called whether the program terminates normally or abnormally, but not when the program ends specifically by calling os._exit. Module atexit supplies a single function called register.
Ensures that func(*args,**kwds) is called at program termination time.