How to use the certbot-nginx.certbot_nginx.configurator.NginxConfigurator function in certbot-nginx

def __init__(self, *args, **kwargs):
        """Initialize an Nginx Configurator.

        :param tup version: version of Nginx as a tuple (1, 4, 7)
            (used mostly for unittesting)

        """
        version = kwargs.pop("version", None)
        super(NginxConfigurator, self).__init__(*args, **kwargs)

        # Verify that all directories and files exist with proper permissions
        self._verify_setup()

        # Files to save
        self.save_notes = ""

        # Add number of outstanding challenges
        self._chall_out = 0

        # These will be set in the prepare function
        self.parser = None
        self.version = version
        self._enhance_func = {"redirect": self._enable_redirect,
                              "staple-ocsp": self._enable_ocsp_stapling}

def rollback_checkpoints(self, rollback=1):
        """Rollback saved checkpoints.

        :param int rollback: Number of checkpoints to revert

        :raises .errors.PluginError: If there is a problem with the input or
            the function is unable to correctly revert the configuration

        """
        super(NginxConfigurator, self).rollback_checkpoints(rollback)
        self.new_vhost = None
        self.parser.load()