newsupernova/app/code/Mageplaza/Core/etc/adminhtml/di.xml

<?xml version="1.0" ?>
<!--
/**
 * Mageplaza
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the mageplaza.com license that is
 * available through the world-wide-web at this URL:
 * https://mageplaza.com/LICENSE.txt
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade this extension to newer
 * version in the future.
 *
 * @category    Mageplaza
 * @package     Mageplaza_Core
 * @copyright   Copyright (c) 2016-2018 Mageplaza (https://www.mageplaza.com/)
 * @license     http://mageplaza.com/LICENSE.txt
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Framework\Notification\MessageList">
        <arguments>
            <argument name="messages" xsi:type="array">
                <item name="mageplaza_validate_message" xsi:type="string">Mageplaza\Core\Model\Message\Validate</item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\Config\Model\Config\Structure\Data">
        <plugin name="mageplaza_module_activate" type="Mageplaza\Core\Model\Config\Structure\Data"/>
    </type>
</config>