from typing import List


def board_to_prolog(board: List[List]) -> str:
    """
    Convert the board from Python object to something Prolog can digest.
    See Board documentation in tic-tac-toe.pl for documentation regarding the
        Prolog data type.
    """
    board_str_list = []
    for row in board:
        for cell in row:
            board_str_list.append(cell.lower() if cell else "0")

    result = str(board_str_list).replace("'", "")
    return result