public function render($template, array $vars = [], array $blocks = [])
    {
        $directory = rtrim($this->directory, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;
        $file = $directory . trim($template, DIRECTORY_SEPARATOR) . $this->suffix;
        $vars += $this->vars;

        $sandbox = new Template($this, $file, $blocks, $this->helpers);
        return $sandbox->compile($vars);
    }