DIP

class PaymentService {
    
    private let database: MySQLDatabase = MySQLDatabase()
    
    func paymentIsValid() {
       // Implementation code
    }
    
    func openDatabase() {
       // Implementation code
    }
    
    func addNewPayment() {
       // Implementation code
    }
    
    func removePaymentByID() {
       // Implementation code
    }
    
    func updatePaymentByID() {
       // Implementation code
    }
}