public function getNCShipments(
        $from = '',
        $to = '',
        $tracking_pin = '',
        array $options = []
    ) {
        if (!isset($from) && !isset($tracking_pin)) {
            $message = 'You must include either a $from date or a $tracking_pin.';
            throw new \InvalidArgumentException($message);
        }
        if (empty($to)) {
            $to = date('YmdHs');
        }
        $this->verifyDates($from, $to);
        $query_params = "from={$from}&to{$to}";

        if (!empty($tracking_pin)) {
            $query_params = "trackingPIN={$tracking_pin}";
        }

        $endpoint = sprintf(
            'rs/%s/ncshipment?%s',
            $this->config['customer_number'],
            $query_params
        );
        $response = $this->get(
            $endpoint,
            ['Accept' => 'application/vnd.cpc.ncshipment-v4+xml'],
            $options
        );
        return $response;
    }