code: def on_serial_port_change(self, serial_port):
          
          if not isinstance(serial_port, ISerialPort):
              raise TypeError("serial_port can only be an instance of type ISerialPort")
          self._call("onSerialPortChange",
                       in_p=[serial_port])
docs: Triggered when settings of a serial port of the
          associated virtual machine have changed.
  
          in serial_port of type :class:`ISerialPort`
  
          raises :class:`VBoxErrorInvalidVmState`
              Session state prevents operation.
          
          raises :class:`VBoxErrorInvalidObjectState`
              Session type prevents operation.