protected static function output_msg($msg) {
        global $CFG, $PAGE;

        // If we are using the web interface we want pretty messages.
        if (!CLI_SCRIPT) {

            $renderer = $PAGE->get_renderer('tool_behat');
            echo $renderer->render_error($msg);

            // Stopping execution.
            exit(1);

        } else {

            // We continue execution after this.
            $clibehaterrorstr = "Ensure you set \$CFG->behat_* vars in config.php " .
                "and you ran admin/tool/behat/cli/init.php.\n" .
                "More info in " . self::DOCS_URL;

            echo 'Error: ' . $msg . "\n\n" . $clibehaterrorstr;
        }
    }