Q$2.$ Create a Python class called BankAccount to simulate a bank account. The class should have the following features:

Initialize the account with a starting balance.

Provide a property to access and modify the account balance.

Ensure that the balance cannot be set to a negative value.

Implement methods deposit$($amount$)$ and withdraw$($amount$)$ to add or subtract funds from the account balance. These methods should also ensure that the provided amount is positive and that there are sufficient funds for withdrawal.