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