docs: 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