@Override
    public String print() {
        StringBuilder report = new StringBuilder();
        report.append("北区业绩报告:\n");
        Iterator iterator = createIterator();
        int totalAmount = 0;
        while (iterator.hasNext()) {
            Achievement achievement = iterator.next();
            report.append("名称 : ").append(achievement.getName())
                    .append(", 金额 : ").append(achievement.getAmount())
                    .append("\n");
            totalAmount += achievement.getAmount();
        }
        report.append("总销售额 : ").append(totalAmount);
        return report.toString();
    }