public function makeTagArray($tagNames)
    {
        if(is_array($tagNames) && count($tagNames) == 1) {
            $tagNames = reset($tagNames);
        }

        if(is_string($tagNames)) {
            $tagNames = explode(',', $tagNames);
        } elseif(!is_array($tagNames)) {
            $tagNames = array(null);
        }

        $tagNames = array_map('trim', $tagNames);

        return array_values($tagNames);
    }