def open(self):
        """Open a (previously initialized) port on dummy_serial."""
        if VERBOSE:
            _print_out('\nDummy_serial: Opening port\n')

        if self._isOpen:
            raise IOError('Dummy_serial: The port is already open')
            
        self._isOpen = True
        self.port = self.initial_port_name
Open a (previously initialized) port on dummy_serial.