public function checkTags($attribute, $params)
{
$result = $this->tags;
$regex = "/[\\^\\[\\]\$\\.\\|\\?\\*\\+\\(\\)\\{\\}\\/\\*\\%\\!\\.\\'\"\\@\\#\\&\\:\\<\\>\\|\\-\\_\\+\\=\\`\\~\\;]/";
if (preg_match($regex, $result)) {
$this->addError('tags', t('Tags must contain characters only'));
}
}