def raise_400(instance, msg=None):
    instance.response.status = 400
    if msg:
        instance.response.body_raw = {'error': msg}
    raise ResponseException(instance.response)
Calculates values required when moving ``node`` relative to
dataset/ETHPy150Open pneff/wsgiservice/wsgiservice/status.py/raise_400--crossover with--dataset/ETHPy150Open django-mptt/django-mptt/mptt/managers.py/TreeManager._calculate_inter_tree_move_values