code: protected function updateNumber(SupplierOrderInterface $order)
      {
          if (0 == strlen($order->getNumber())) {
              $this->numberGenerator->generate($order);
  
              return true;
          }
  
          return false;
      }
docs: Updates the number.
  
  @param SupplierOrderInterface $order
  
  @return bool Whether or not the supplier order number has been changed.