Starting with support for Gitlab API v4, the following classes gitlab.Gitlab, base.GitlabObject and base.RESTObject are not pickle-able because of the references to modules they keep as properties (_module and _objects).

I run into the issue when I use a multiprocessing.Pool and tqdm to run git operations in parallel and show a progress bar.

I created and am currently using a small patch at a8f1493. If the issue and a possible approach are approved I have some time to invest to create a proper PR.