def METHOD_NAME(self, user_stories):
    role_points = [us.role_points.all() for us in user_stories]
    flat_role_points = itertools.chain(*role_points)
    flat_role_dicts = map(lambda x: {x.role_id: x.points.value if x.points.value else 0}, flat_role_points)
    return dict_sum(*flat_role_dicts)