Thanks for your contribution. What use-case do you have for this? How can I test it?

My use case is to compute statistics. One of them being the number of commits not part of a merge request.
So for a project, I retrieve all of its commits and then all the commits linked to an MR and do something like :

merge_requets_commits = XXX
commits_not_linked_to_mr = [commit for commit in project.commits.list(all=True, ref_name='master') if commit not in merge_requets_commits]

The not in part requires __eq__ to be defined on RESTObject.

For the __hash__, I often transform commits lists into sets to ensure uniqueness.

Sorry I forgot about the tests, I'll add some of them to test the changes.