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

    public function validate($vatNumber)
    {
        if (strlen($vatNumber) != 9) {
            return false;
        }
        if (!is_numeric(substr($vatNumber, 1, 6))) {
            return false;
        }
        $checksum = $vatNumber[8];
        $fieldC1 = $vatNumber[0];
        if (ctype_alpha($checksum) && in_array($fieldC1, $this->allowedC1Alphabetic)) {
            // Juridical entities other than national ones
            $checkval = $this->validateJuridical($vatNumber);
        } elseif (ctype_digit($checksum) && in_array($fieldC1, $this->allowedC1Numeric)) {
            // National juridical entities
            $checkval = $this->validateNational($vatNumber);
        } else {
            return false;
        }
        if ($checksum != $checkval) {
            return false;
        }
        return true;
    }