Parse available informations about book from the book details page.

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

    Returns:
        obj: :class:`structures.Publication` instance with book details.

def _process_book(html_chunk):
    """
    Parse available informations about book from the book details page.

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

    Returns:
        obj: :class:`structures.Publication` instance with book details.
    """
    title, url = _parse_title_url(html_chunk)
    book_format, pages, isbn = _parse_format_pages_isbn(html_chunk)

    # required informations
    pub = Publication(
        title=title,
        authors=_parse_authors(html_chunk),
        price=_parse_price(html_chunk),
        publisher="Grada"
    )

    # optional informations
    pub.optionals.URL = url
    pub.optionals.ISBN = isbn
    pub.optionals.pages = pages
    pub.optionals.format = book_format
    pub.optionals.sub_title = _parse_subtitle(html_chunk)
    pub.optionals.description = _parse_description(html_chunk)

    return pub