Context Managers in Python

context_managers.py

import pickle


class Board:
    def __init__(self):
        self.board = [['.']*3 for i in range(3)]
      
    def mark(self, x, y, sign):
        self.board[x][y] = sign
    
    def serialize(self):
        with open('board.pickle', 'wb') as f:
            pickle.dump(self, f, pickle.HIGHEST_PROTOCOL)
    
    @staticmethod
    def deserialize():
        with open('board.pickle', 'rb') as f:
            board = pickle.load(f)
            return board

board = Board()
board.mark(0, 0, 'o')
board.serialize()
print(board.board)

board2 = Board.deserialize()
print(board2.board)
print(type(board2))


class Contextmanager:
    def __init__(self, generator):
        self.generator = generator

    def __call__(self, *args, **kwargs):
        self.args, self.kwargs = args, kwargs
        return self

    def __enter__(self):
        self.generator_instance = self.generator(*self.args, **self.kwargs)
        return next(self.generator_instance)

    def __exit__(self, *args):
        try:
            next(self.generator_instance)
        except StopIteration:
            print("StopIteration")
        return self

# get_board = Contextmanager(get_board)
    
@Contextmanager
def get_board():
    print(f"Deserializing board")
    board = Board.deserialize()
    yield board
    print(f"Serializing board")

with get_board() as board:
    board.mark(0, 1, 'x')
    print(board.board)