How to Implement the Command Pattern with Undo in Python

class Command:
    def execute(self):
        raise NotImplementedError

    def undo(self):
        raise NotImplementedError


class AddTextCommand(Command):
    def __init__(self, document, text):
        self.document = document
        self.text = text

    def execute(self):
        self.document.append(self.text)

    def undo(self):
        self.document.pop()


class RemoveLastCommand(Command):
    def __init__(self, document):
        self.document = document
        self.removed_text = None

    def execute(self):
        self.removed_text = self.document.pop()

    def undo(self):
        self.document.append(self.removed_text)


class CommandHistory:
    def __init__(self):
        self.history = []
        self.redo_stack = []

    def execute(self, command):
        command.execute()
        self.history.append(command)
        self.redo_stack.clear()

    def undo(self):
        if self.history:
            command = self.history.pop()
            command.undo()
            self.redo_stack.append(command)

    def redo(self):
        if self.redo_stack:
            command = self.redo_stack.pop()
            command.execute()
            self.history.append(command)


if __name__ == "__main__":
    doc = []
    history = CommandHistory()

    history.execute(AddTextCommand(doc, "Hello"))
    history.execute(AddTextCommand(doc, "World"))
    history.execute(RemoveLastCommand(doc))
    print("After commands:", doc)

    history.undo()
    print("After one undo:", doc)

    history.undo()
    print("After two undos:", doc)

    history.redo()
    print("After redo:", doc)