public static function _groupAutoUpdateHelper(
        Api\GroupAutoUpdate $autoUpdate
    ) {
        $fields = [ 'to' => $autoUpdate->getRecipient() ];

        if (null != $autoUpdate->getAddFirstWord()) {
            $fields['add']['first_word'] = $autoUpdate->getAddFirstWord();
        }

        if (null != $autoUpdate->getAddSecondWord()) {
            $fields['add']['second_word'] = $autoUpdate->getAddSecondWord();
        }

        if (null != $autoUpdate->getRemoveFirstWord()) {
            $fields['remove']['first_word'] = $autoUpdate->getRemoveFirstWord();
        }

        if (null != $autoUpdate->getRemoveSecondWord()) {
            $fields['remove']['second_word'] = $autoUpdate->getRemoveSecondWord();
        }

        return $fields;
    }