public static function extractWhereValues($conditions) 
    {
        $values = array();
        if (!$conditions) {
            return $values;
        }

        if (is_array($conditions)) {
            if (array_values($conditions) !== $conditions) {
                $values = self::_extractWhereAssociativeValues($conditions);
            } else {
                $values = self::_extractWhereRegularValues($conditions);
            }
        }
        return $values;
    }