test_weakref
Basic Weak References
-- Liveness and referent identity
-- Reference objects with callbacks
-- Proxy objects with callbacks
-- Re-use of weak reference objects
     reference objects
     proxy objects
clearing ref 2
clearing ref 1
clearing ref 2
clearing ref 1

Weak Valued Dictionaries
objects are stored in weak dict
weak dict test complete

Non-callable Proxy References
XXX -- tests not written!

Callable Proxy References