docs: def _comports():
      '''
      Returns
      -------
      pandas.DataFrame
          Table containing descriptor, and hardware ID of each available COM
          port, indexed by port (e.g., "COM4").
      '''
      return (pd.DataFrame(list(map(list, serial.tools.list_ports.comports())),
                           columns=['port', 'descriptor', 'hardware_id'])
              .set_index('port'))