yursudoku.py

def fetch_new_puzzle(difficulty):
    """Get a new puzzle from the online source.
       Difficulties are from 1 to 5 maybe? Integers.
       Boards are indexed x and y, where x is the row
       number and y is the column number.
    """
    page_text = urlopen("http://www.free-sudoku.com/sudoku.php?mode=%s" %
                   difficulty ).read()
    tree = html.fromstring(page_text)

    board = new_board()
    for x, y in product(range(9), range(9)):
        element_id = (x * 9) + y + 1
        text_content = tree.get_element_by_id(element_id).text_content()
        value = int(text_content) if text_content else None
        board[(x,y)] = value

    return board