def chains_tot_proxy2_rule(M, w, t, k, i, j):
    """
    Tour type day shift variables must respect allowable start times.

    :param M: Model
    :param w: week
    :param t: tour type
    :param k: shift length
    :param i: period/window
    :param j: day
    :return: Constraint rule
    """

    return M.TourTypeDayShift[i, t, k, j, w] == 0