fetchMails example

$mapping = [];
        foreach ($events as $event) {
            $config = json_decode((string) $event['config'], true, 512, \JSON_THROW_ON_ERROR);
            if (!isset($config['mail_template_type_id'])) {
                continue;
            }

            $mapping[] = ['event_name' => $event['event_name'], 'typeId' => $config['mail_template_type_id']];
        }

        $mails = $this->fetchMails($connection, array_column($mapping, 'typeId'));

        $mails = $this->map($mapping, $mails);

        $this->insertMails($connection, $mails);

        // generate entries for order state mails         $ids = $this->getTypeIds($connection, [
            'order_delivery.state.cancelled',
            'order_delivery.state.returned',
            'order_delivery.state.returned_partially',
            'order_delivery.state.shipped',