public function getNationalSignificantNumber(PhoneNumber $number)
    {
        // If leading zero(s) have been set, we prefix this now. Note this is not a national prefix.
        $nationalNumber = '';
        if ($number->isItalianLeadingZero() && $number->getNumberOfLeadingZeros() > 0) {
            $zeros = str_repeat('0', $number->getNumberOfLeadingZeros());
            $nationalNumber .= $zeros;
        }
        $nationalNumber .= $number->getNationalNumber();
        return $nationalNumber;
    }