Fix some set algebra methods of WeakSet objects.
authorAntoine Pitrou <solipsis@pitrou.net>
Sun, 4 Mar 2012 20:16:52 +0000 (21:16 +0100)
committerAntoine Pitrou <solipsis@pitrou.net>
Sun, 4 Mar 2012 20:16:52 +0000 (21:16 +0100)

Trivial merge