There's a quirk in theCreateMixin when checking for required attributes in_check_missing_create_attrs, which requires a data dict. But some create methods don't require additional data, e.g. if the only required attribute is already provided by their parent manager id (e.g. for project export, seehttps://docs.gitlab.com/ee/api/project_import_export.html).

This means the docs are sometimes asking people to pass an empty dict which I think is confusing for newcomers (and maybe unpythonic?).

This small fix allows usingcreate() without passing a dict. TheUpdateMixin is doing something similar withnew_data = new_data or {} but I thought this is a bit more explicit with None.

I didn't add any checks as the data is already validated in_check_missing_create_attrs based on each Manager's_create_attrs and is already tested (see below), so I hope I covered everything :)