def copy_board(board):
    """
    Board's copy.

     Examples:
    >>> game = board(10)
    >>> set_alive(game, (4,7), True)
    >>> game2 = copy_board(game)
    >>> game2 is game
    False
    >>> is_alive(game2, (4,7))
    True

    :param board: The game's board.
    :return: A new board which is a copy of the current one.
    """

    return board.copy()