determine if a sudoku is valid according to sudoku puzzles the rules the sudoku board could be partially filled where empty cells are filled with the character
def is_valid_sudoku(self, board):
    seen = []
    for i, row in enumerate(board):
        for j, c in enumerate(row):
            if c != '.':
                seen += [(c,j),(i,c),(i/3,j/3,c)]
    return len(seen) == len(set(seen))