3.4 As a way of managing a backup/restore functionality, it has been decided to subclass the QTableWidget class to implement a classic memento design pattern. The start of the class definition is provided below. class MyTableWidget: public QTableWidget \{ private: friend class MyTableWidgetMemento; MyTableWidget (); MyTableWidgetMemento* createMemento (); void setMemento (MyTableWidgetMemento *m); \}; 3.4.1 What components usually make up the classic memento pattern, and which classes in this scenario would represent those components? 3.4.2 Explain why this implementation of the classic memento patten is correct or not. Marks are only awarded for the explanation