/**
  * @param Account $entity
  * @return array
  */
 protected function buildTreeRecursive(Account $entity)
 {
     $entities = [];
     $children = $entity->getChildren();
     foreach ($children->toArray() as $child) {
         $entities[] = $child;
         $entities = array_merge($entities, $this->buildTreeRecursive($child));
     }
     return $entities;
 }