Support opcode 0x52

[SuperSandro2000]

When trying to unpickle a sift-ring-builder file I get the following error:

Pickle Machine failed on opcode:0x52. Stack size:25. Memo size:32. Cause:Unresolvable Python global value

I created the file with the following command and also attached it: swift-ring-builder test.builder create 10 3 1 test.zip