Connect to a device via TCP/IP directly.

def connect(self, host: str = '192.168.0.3', port: Union[int, str] = 5555) -> None:
        '''Connect to a device via TCP/IP directly.'''
        self.device_sn = f'{host}:{port}'
        if not is_connectable(host, port):
            raise ConnectionError(f'Cannot connect to {self.device_sn}.')
        self._execute('connect', self.device_sn)