AccountBalance Class with Time-Based Grants and Spending

openai Implement an AccountBalance class with the following three methods: addGrant, addSpend, and getBalance. Each method includes a timestamp indicating when the add, spend, or getBalance operation is executed. The Grant also includes an expiration time. Specific requirements are as follows: The addGrant(amount: float, timestamp: int, expire: int) method is used to add a grant amount with a specified expiration time. The addSpend(amount: float, timestamp: int) method records an expenditure. The getBalance(timestamp: int) -> float method calculates the current balance at a given point in time. The implementation should exclude expired grants from the balance and ensure transactions are processed in chronological order. Example Input addGrant(100, 1, 5) addSpend(50, 2) getBalance(3)