public function changeInvoiceToConcept($messageKey, $code)
    {
        $pdfMessage = '';
        $invoiceSettings = $this->config->getInvoiceSettings();
        $concept = $invoiceSettings['concept'];
        if ($concept == PluginConfig::Concept_Plugin) {
            $this->invoice[Tag::Customer][Tag::Invoice][Tag::Concept] = Api::Concept_Yes;
            $emailAsPdfSettings = $this->config->getEmailAsPdfSettings();
            if ($emailAsPdfSettings['emailAsPdf']) {
                $pdfMessage = ' ' . $this->t('message_warning_no_pdf');
            }
        }

        if ($messageKey !== '') {
            $message = $this->t($messageKey) . $pdfMessage;
            if (func_num_args() > 2) {
                $args = func_get_args();
                $message = vsprintf($message, array_slice($args, 2));
            }
            $this->result->addWarning($code, '', $message);
        }
    }