Implementation of NAPALM method commit_config.

def commit_config(self, message=""):
        """Implementation of NAPALM method commit_config."""
        if message:
            raise NotImplementedError(
                "Commit message not implemented for this platform"
            )
        commands = [
            "copy startup-config flash:rollback-0",
            "configure session {}".format(self.config_session),
            "commit",
            "write memory",
        ]

        self.device.run_commands(commands)
        self.config_session = None