Code for the article: https://aleksandarjakovljevic.com/sonata-admin-modify-validation-groups-in-an-admin-extension/ part #1

AbstractAdmin.php

<?php

// ....

public function getFormBuilder()
 {
   $this->formOptions['data_class'] = $this->getClass();
   $formBuilder = $this->getFormContractor()->getFormBuilder(
     $this->getUniqid(),
     $this->formOptions
   );
   $this->defineFormBuilder($formBuilder);
   return $formBuilder;
 }