docs: def create_question_pdfs(nb, pages_per_q, folder, zoom) -> list:
      """
      Converts each cells in tbe notebook to a PDF named something like
      'q04c.pdf'. Places PDFs in the specified folder and returns the list of
      created PDF locations.
      """
      html_cells = nb_to_html_cells(nb)
      q_nums = nb_to_q_nums(nb)
  
      os.makedirs(folder, exist_ok=True)
  
      pdf_options = PDF_OPTS.copy()
      pdf_options['zoom'] = ZOOM_FACTOR * zoom
  
      pdf_names = []
      for question, cell in zip(q_nums, html_cells):
          # Create question PDFs
          pdf_name = os.path.join(folder, '{}.pdf'.format(question))
  
          pdfkit.from_string(cell.prettify(), pdf_name, options=pdf_options)
  
          pad_pdf_pages(pdf_name, pages_per_q)
  
          print('Created ' + pdf_name)
          pdf_names.append(pdf_name)
      return pdf_names