code: protected function removeItem($item)
      {
          if (!$this->supportsCascadeUpdate()) {
              $this->db->createCommand()
                  ->delete($this->itemChildTable, ['or', '[[parent]]=:name', '[[child]]=:name'], [':name' => $item->name])
                  ->execute();
              $this->db->createCommand()
                  ->delete($this->assignmentTable, ['item_name' => $item->name])
                  ->execute();
          }
  
          $this->db->createCommand()
              ->delete($this->itemTable, ['name' => $item->name])
              ->execute();
  
          $this->invalidateCache();
  
          return true;
      }
docs: {@inheritdoc}