from typing import List


def checkio(tic):
    success_x = 'XXX'
    success_o = 'OOO'

    for row in tic:
        horizontal = row[0] + row[1] + row[2]
        if horizontal in success_x:
            return "X"
        elif horizontal in success_o:
            return "O"

    vertical_tip = list(zip(*tic))

    for row in vertical_tip:
        vertical = row[0] + row[1] + row[2]
        if vertical in success_x:
            return "X"
        elif vertical in success_o:
            return "O"

    diagonal_first = tic[0][0] + tic[1][1] + tic[2][2]
    diagonal_second = tic[0][2] + tic[1][1] + tic[2][0]

    if diagonal_first or diagonal_second in success_x:
        return "X"

    elif diagonal_first or diagonal_second in success_x:
        return "O"

    return "D"


if __name__ == '__main__':
    print("Example:")
    print(checkio(["X.O",
                   "XX.",
                   "XOO"]))

    #These "asserts" using only for self-checking and not necessary for auto-testing
    # assert checkio([
    #     "X.O",
    #     "XX.",
    #     "XOO"]) == "X", "Xs wins"
    # assert checkio([
    #     "OO.",
    #     "XOX",
    #     "XOX"]) == "O", "Os wins"
    assert checkio([
        "OOX",
        "XXO",
        "OXX"]) == "D", "Draw"
    # assert checkio([
    #     "O.X",
    #     "XX.",
    #     "XOO"]) == "X", "Xs wins again"
    # print("Coding complete? Click 'Check' to review your tests and earn cool rewards!")