Python - Run a code at exit using weak references

""" Simulating atexit using weak references """

# Don't use this code - it is just for illustration.
# Generally speaking it is better not to rely on order of
# gc to implement a feature.

import weakref

class C: pass

def goodbye(param):
    print 'Bye.',param

x=weakref.ref(C, goodbye)

if __name__ == '__main__':
    print 3+4
    print 8+9
    print globals()