protected function getSforInVariableNode($variable)
    {
        $env = new \Twig_Environment(new \Twig_Loader_Array());
        $parser = new \Twig_Parser($env);
        $lexer = new \Twig_Lexer($env);
        $stream = $lexer->tokenize(new \Twig_Source('{{'.$variable.'}}', 'variables'));

        return $parser->parse($stream)->getNode('body')->getNode(0)->getNode('expr')->getNode('node');
    }