Parse format, number of pages and ISBN.

    Args:
        html_chunk (obj): HTMLElement containing slice of the page with details.

    Returns:
        tuple: (format, pages, isbn), all as string.

def _parse_format_pages_isbn(html_chunk):
    """
    Parse format, number of pages and ISBN.

    Args:
        html_chunk (obj): HTMLElement containing slice of the page with details.

    Returns:
        tuple: (format, pages, isbn), all as string.
    """
    ppi = get_first_content(
        html_chunk.find("div", {"class": "price-overflow"})
    )

    if not ppi:
        return None, None, None

    # all information this function should parse are at one line
    ppi = filter(lambda x: x.strip(), ppi.split("<br />"))[0]

    # parse isbn
    isbn = dhtmlparser.parseString(ppi)
    isbn = isbn.find("b")
    isbn = isbn[0].getContent() if isbn else None

    # parse pages and format
    pages = None
    book_format = None
    details = ppi.split("|")

    if len(details) >= 2:
        book_format = details[0].strip()
        pages = details[1].strip()

    return book_format, pages, isbn