public function addCachedField($arFieldList)
    {
        if (empty($arFieldList)) {
            return;
        }

        if (empty($this->cached) || !is_array($this->cached)) {
            $this->cached = [];
        }

        if (is_string($arFieldList)) {
            $arFieldList = [$arFieldList];
        }

        $this->cached = array_merge($this->cached, $arFieldList);
        $this->cached = array_unique($this->cached);
    }