code: def extra_info(port):
      
      extra_items = []
      if port.manufacturer:
          extra_items.append("vendor '{}'".format(port.manufacturer))
      if port.serial_number:
          extra_items.append("serial '{}'".format(port.serial_number))
      if port.interface:
          extra_items.append("intf '{}'".format(port.interface))
      if extra_items:
          return ' with ' + ' '.join(extra_items)
      return ''
docs: Collects the serial nunber and manufacturer into a string, if
         the fields are available.