    public static function is_exist($vars)
    {
        $opt = self::get($vars);

        if (false !== $opt) {
            return true;
        } else {
            return false;
        }
    }
The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.