public function filterByHidden($hidden = null, $comparison = null)
    {
        if (is_string($hidden)) {
            $hidden = in_array(strtolower($hidden), array('false', 'off', '-', 'no', 'n', '0', '')) ? false : true;
        }

        return $this->addUsingAlias(CategoryTableMap::COL_HIDDEN, $hidden, $comparison);
    }