code: def pdf_result(pdf_binary: bytes,
                 extraheaders: TYPE_WSGI_RESPONSE_HEADERS = None,
                 filename: str = None) -> WSGI_TUPLE_TYPE:
      
      extraheaders = extraheaders or []
      if filename:
          extraheaders.append(
              ('content-disposition', 'inline; filename="{}"'.format(filename))
          )
      contenttype = 'application/pdf'
      if filename:
          contenttype += '; filename="{}"'.format(filename)
      # log.debug("type(pdf_binary): {}", type(pdf_binary))
      return contenttype, extraheaders, pdf_binary
docs: Returns ``(contenttype, extraheaders, data)`` tuple for a PDF.