private function generateLabeledPrices(array $prices)
    {
        $response = [];

        foreach ($prices as $item => $price)
        {
            if ($price < 1)
            {
                $this->logger->warning('Invalid or negative price passed to "sendInvoice"');
                throw new \Exception('Invalid or negative price passed to "sendInvoice"');
            }

            // Format the price value following the official guideline:
            // https://core.telegram.org/bots/api#labeledprice
            $formatted_price = intval($price * 100);
            array_push($response, ['label' => $item, 'amount' => $formatted_price]);
        }

        return json_encode($response);
    }