docs: def _parse_pages_binding(details):
      """
      Parse number of pages and binding of the book.
  
      Args:
          details (obj): HTMLElement containing slice of the page with details.
  
      Returns:
          (pages, binding): Tuple with two string or two None.
      """
      pages = _get_td_or_none(
          details,
          "ctl00_ContentPlaceHolder1_tblRowRozsahVazba"
      )
  
      if not pages:
          return None, None
  
      binding = None  # binding info and number of pages is stored in same string
      if "/" in pages:
          binding = pages.split("/")[1].strip()
          pages = pages.split("/")[0].strip()
  
      if not pages:
          pages = None
  
      return pages, binding