tox -e pylint result:

************* Module gitlab.mixins
gitlab/mixins.py:121:19: E1102: self._obj_cls is not callable (not-callable)
gitlab/mixins.py:125:15: E1102: self._obj_cls is not callable (not-callable)
gitlab/mixins.py:158:15: E1102: self._obj_cls is not callable (not-callable)
gitlab/mixins.py:248:20: E1102: self._obj_cls is not callable (not-callable)
gitlab/mixins.py:304:15: E1102: self._obj_cls is not callable (not-callable)
gitlab/mixins.py:405:15: E1102: self._obj_cls is not callable (not-callable)

Your code has been rated at 9.94/10 (previous run: 10.00/10, -0.06)