public function preRender($pugCode)
    {
        $parts = $this->getPugCodeLayoutStructure($pugCode);
        $className = get_class($this);
        foreach ($this->replacements as $name => $callable) {
            $parts[0] .= ":php\n" .
                "    if (!function_exists('$name')) {\n" .
                "        function $name() {\n" .
                "            return call_user_func_array($className::getGlobalHelper('$name'), func_get_args());\n" .
                "        }\n" .
                "    }\n";
        }

        return implode('', $parts);
    }