@Override
	public String toString() {
		String transactionItems = "";
		int num = this.transaction.getItemSet().size();
		for (int i = 0; i < num; i++) {
			String item = this.transaction.getItemSet().get(i).toString();
			transactionItems = transactionItems + item;
			if (i < num - 1) {
				transactionItems = transactionItems + ",";
			}

		}
		return "{" + transactionItems + "}";//don't forget the opening and closing braces

	}