Demo.kt

object CustomerData {
    var customerId = “123”
    var name = “John”
    var totalBill = 284.34
    var purchasedItems: List<Item> = arrayListOf()

    fun addItem(item: Item) {
        purchasedItems.add(item)
        totalBill = calculateBill()
    }

    fun calculateBill(): Float {
        // Some calculations
        return newBill;
    }
}