We now allow Pickle Protocol v2 __getnewargs__() to contain
The unpickler uses a new strategy for handling references.
It now places Proxy objects into the referencing machinery
to break dependencies between construction arguments and
A final sweep is done at the end of restore() to swap proxies
for their real instances. This allows for proper referencing
within objects returned by __getnewargs__().
Signed-off-by: David Aguilar <email@example.com>