private function helpAction($message = null)
    {
        if ($message !== null) {
            $this->report = new Report(
                Report::TYPE_ERROR,
                $message . PHP_EOL
            );
        }

        $helpReport = new Report(
            Report::TYPE_INFO,
            "Usage: " . __CLASS__ . " <mode> [<args>]" . PHP_EOL . PHP_EOL
            . "Available modes:" . PHP_EOL
            . "   list        get list of all deliveries" . PHP_EOL
            . "   archive     archive all deliveries use --force to forge regeneration" . PHP_EOL
            . "   unarchive   unarchive all deliveries --force to forge unarchiving" . PHP_EOL
            . "   delete      delete all archives deliveries" . PHP_EOL
        );

        if ($this->report) {
            $this->report->add($helpReport);
        } else {
            $this->report = $helpReport;
        }
    }