DragonBe\Vies\Validator\ValidatorLV::validate PHP Method

    public function validate($vatNumber)
    {
        if (strlen($vatNumber) != 11) {
            return false;
        }
        if ((int) $vatNumber[0] <= 3) {
            return false;
        }
        $weights = array(9, 1, 4, 8, 3, 10, 2, 5, 7, 6);
        $checksum = (int) substr($vatNumber, -1);
        $checkval = $this->sumWeights($weights, $vatNumber);
        $checkval = 3 - $checkval % 11;
        if ($checkval == -1) {
            return false;
        }
        if ($checkval < -1) {
            $checkval += 11;
        }
        if ($checksum != $checkval) {
            return false;
        }
        return true;
    }