def set_square(square, mark):
    """ Sets the value of the given square. """
    row_i = square_row(square) - 1
    col_i = ord(square_col(square)) - ord(A)
    board[row_i][col_i] = mark  # note how this and get_square are the ONLY
                                # functions which directly use board!
 Sets the value of the given square. 
recipes/Python/576661_TicTacToe/recipe-576661.py