public function renderInitialize(\Twig_Environment $environment, $options = null)
    {
        if (is_null($options)) {
            $options = array();
        }

        $defaults = array();

        $this->setOptionIfNotSet($defaults, $this->accountVarName, $this->accountId);

        // Things set in $options will override things set in $defaults.
        $options = array_merge($defaults, $options);

        if (!$this->isOptionSet($options, $this->accountVarName)) {
            throw new \Twig_Error_Runtime(
                "The google_analytics_initialize function depends on a Google Analytics account ID. You can either pass this along in the initialize_google_analytics function ($this->accountVarName), provide a variable under 'parameters.google.analytics.account_id'."
            );
        }

        $template = $environment->loadTemplate('KunstmaanSeoBundle:GoogleAnalyticsTwigExtension:init.html.twig');

        return $template->render($options);
    }