我怎样才能返回一个范围锁？

Consider, say, a collection of account balances. And then you have a complex function that needs to check the balances of a few different accounts and then adjust the balances of a few different accounts. The operations need to be atomic with respect to other users of the collection. You have a collection class whose primary job is to provide this kind of atomicity. What's the 'right' way?Consider, say, a collection of account balances