Don't try this at home

go defer for python.py

import inspect
frames={}
class MyObj:
    def __init__(self):
        self.callbacks = []

    def __del__(self):
        print "callbacks"
        for thing in self.callbacks:
            try:
                thing()
            except Exception:
                pass

    def append(self, thingy):
        self.callbacks.append(thingy)

def defer(thingy):
    frame = inspect.stack()[1][0]
    if '__atexit' not in frame.f_locals:
        frame.f_locals['__atexit'] = MyObj()
    frame.f_locals['__atexit'].append(thingy)

def foo():
    f = open('/etc/hosts')
    print "before defer"
    defer (f.close)
    print "after defer"

foo()
print "all callbacks should be called before this point"