* @param cs A <code>ChangeSet</code> to update.
     */
    public void csSetTax(int tax, ChangeSet cs) {
        setTax(tax);
        if (recalculateBellsBonus()) {
            cs.add(See.only(this), this);
        } else {
            cs.addPartial(See.only(this), this, "tax");
        }
    }