    public function compareTo($l) {
        if ($l === false) return false;
        if ($l->unit !== $this->unit) {
            $converter = new HTMLPurifier_UnitConverter();
            $l = $converter->convert($l, $this->unit);
            if ($l === false) return false;
        }
        return $this->n - $l->n;
    }
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.