argue-2.0.0-alpha4/modules/argue_demo/argue_demo.install

<?php

function argue_demo_uninstall() {
  $default_content_conf = \Drupal::service('extension.list.module')->getExtensionInfo('argue_demo')['default_content'];

  foreach($default_content_conf as $entity_type => $uuid_array) {
    /** @var \Drupal\Core\Entity\EntityStorageInterface $storage */
    $storage = \Drupal::service('entity_type.manager')->getStorage($entity_type);
    foreach ($uuid_array as $uuid) {
      /** @var \Drupal\Core\Entity\EntityInterface $entity */
      $entities = $storage->loadByProperties(['uuid' => $uuid]);
      foreach ($entities as $entity) {
        $entity->delete();
      }
    }
  }
}