The copy module will not properly copy/deepcopy weakrefs, it will bomb
out with __new__ not having enough args. This is a problem b/c it makes
deepcopying of objects that make use of Weak(Key|Value)Dictionaries
difficult.

To replicate:

import copy, weakref
class Test(object): pass
t = Test()
wr = weakref.ref(t)
wr_new = copy.copy(wr)