@classmethod
    def activity_related_models(cls):
        pass
Get the end point of the range.  Not a copy, so changing this alters
dataset/ETHPy150Open GetStream/stream-django/stream_django/activity.py/Activity.activity_related_models--crossover with--dataset/ETHPy150Open pyjs/pyjs/pyjswidgets/pyjamas/selection/Range.py/Range.getEndPoint