code: def _parse_format_pages_isbn(html_chunk):
      
      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
docs: 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.