Design a class that keeps track of purchases at Gold City Mall. A voucher is assigned to an individual coming to Gold City. When a voucher is first issued, the balance is set to some rupees. If the user does not specify the rupees initially, then the balance is set to 1000 Rs. Every time users buys an items, points are deducted from the balance. If the balance becomes negative or item price is more than the current balance, the purchase of items is not allowed. Implement the Voucher class such it supports the key functionalities stated above