Problem with pickle and old version of library six in the repository.

[bondarevts]

If you import pymc and try to pickle, as example, Ellipsis object, then sometimes you will see an error ImportError: No module named 'winreg':

> python -c "import pymc, pickle; pickle.dumps(...)"

It reproduces not all the time, but usually for second or third try.

OS X El Capitan 10.11.5 Python 3.5.1 pymc 2.3.6

As I understand, the reason is that pymc uses outdated version of six library.

The problem is that pymc imports this internally packaged module six. When six is imported, it creates MovedModule objects which will be stored in sys.modules.

When Pickle tries to store object by using function save_global it goes through all objects inside sys.modules and try to get attribute by name of saved object.

When pymc.six.MovedModule.__getattr__ is called, it will try to load this module and will fail if this module is not in the system.

The new version of six package doesn't have this problem inside.

[fonnesbeck]

Thanks. I will remove pymc.six and replace it with a dependency on the current six package.