Implementing memo mode using Python

Memo pattern is a behavioral design pattern used to capture and save the internal state of an object without breaking encapsulation, so that it can be restored to its previous state in the future. In Python, the following steps can be used to implement memo mode: 1. Create an Originator class that contains the attributes and methods that need to be backed up. This class is responsible for creating a Memonto object and storing the current state in the memo. 2. Create a Memento class that contains the object states that need to be stored. Memo objects typically store the state of the Originator object. 3. Create a Caretaker class, which is responsible for managing memo objects. It can store a list of memo objects and provide methods for saving and restoring them. The following is an example code for a simple memo mode: python #Creating the Originator class class Originator: def __init__(self, state): self._state = state def create_memento(self): return Memento(self._state) def restore_from_memento(self, memento): self._state = memento.get_state() def get_state(self): return self._state def set_state(self, state): self._state = state #Create Memento class class Memento: def __init__(self, state): self._state = state def get_state(self): return self._state #Create Caretaker Class class Caretaker: def __init__(self): self._mementos = [] def add_memento(self, memento): self._mementos.append(memento) def get_memento(self, index): return self._mementos[index] #Using memo mode originator = Originator("State 1") Print ("Initial state:", originator. get_state()) caretaker = Caretaker() caretaker.add_memento(originator.create_memento()) originator.set_state("State 2") Print ("Modified state:", originator. get_state()) originator.restore_from_memento(caretaker.get_memento(0)) Print ("Restored state:", originator. get_state()) In the example code above, the Originator class represents the backed up object, the Memento class represents the memo object, and the Caretaker class is responsible for managing the memo object. Run the above code, and the output will be: Initial state: State 1 Modified state: State 2 Restored state: State 1 This indicates that the memo mode successfully saved the state of the object and was able to restore it to its previous state when needed.