import gc

counter = 100

class Dispenser(object):
    def __enter__(self):
        global counter
        self.val = [counter]  # Proxy for VecGetArray -> numpy view
        counter += 1
        return self.val
    def __exit__(self,*args):
        reflist = gc.get_referrers(self.val)
        n = len(reflist)
        print('__exit__: %r, nrefs=%r, refs=%r' % (self.val, n, reflist))

def main():
    with Dispenser() as a, Dispenser() as b, Dispenser() as c:
        x = [a,c] # Proxy for referencing memory through a numpy view
    ## pre-2.7
    # with Dispenser() as a:
    #     with Dispenser() as b:
    #         with Dispenser() as c:
    #             x = [a,c]

if __name__ == '__main__':
    main()