/**
  * @return void
  */
 private function clearItems()
 {
     $items = $this->client->getItems();
     while (count($items['entities']) > 0) {
         foreach ($items['entities'] as $item) {
             $this->client->deleteItem($item['id'], true);
         }
         $items = $this->client->getItems();
     }
 }