/**
* Generate a Luhn compliant number.
*
* @param string $prefix
* @return string
*/
public static function generateLuhnNumber($partialValue)
{
if (!preg_match('/^\\d+$/', $partialValue)) {
throw new InvalidArgumentException('Argument should be an integer.');
}
return $partialValue . Luhn::computeCheckDigit($partialValue);
}