Ios 多协议和类继承混乱，Swift

所以我知道一个类只能继承一个类，但可以继承多个协议.我看着这里的一些代码，搞不懂为什么Swift会抛给我一个错误.

protocol PaymentViewModelConfigurable: ViewModelWithResult {
    
}

class ViewModelWithResult {
    func printWithResultClass() {
        print("In View Model with result class")
    }
}

class PaymentViewModel: PaymentViewModelConfigurable {
    
    
}


class MainOne {
    let viewModel: PaymentViewModelConfigurable = PaymentViewModel()
}

所以我假设这是可以的，因为我的PaymentViewModel类继承了一个协议，而该协议继承了一个类.

但是，如果我在我的视图模型上将逻辑更改为继承协议和类，它将很好地?

protocol PaymentViewModelConfigurable: ViewModelWithResult {
    func payments()
}

class ViewModelWithResult {
    func printWithResultClass() {
        print("In View Model with result class")
    }
}

class PaymentViewModel: ViewModelWithResult, PaymentViewModelConfigurable {
    func payments() {
        print("Payments")
    }
}


class MainOne {
    let viewModel: PaymentViewModelConfigurable = PaymentViewModel()
    
    init() {
        viewModel.payments()
    }
}

以下是出现的错误:

'PaymentViewModelConfigurable' requires that 'PaymentViewModel' inherit from 'ViewModelWithResult'

Type 'PaymentViewModel' does not conform to protocol 'PaymentViewModelConfigurable'