Magento 2 Module development or Magento 2 Hello World Simple Module trends is increase rapidly while Magento release official version. That why we - Mageplaza - are wring about a topic that introduces how to create a simple Hello World module in Magento 2.
In php constructor method is __construct, not _construct
For example, in this file https://github.com/mageplaza/magento-2-sample-module/blob/master/Model/Post.php
_construct is used instead of __construct
UPD Nevermind, I'm stupid, its an internal method for magento