code: public function saveEach(CollectionInterface $objItems, $timestamp = 0)
      {
          if (null === $timestamp) {
              // @codingStandardsIgnoreStart
              @\trigger_error(
                  'Not passing a timestamp has been deprecated and will cause an error in MetaModels 3',
                  E_USER_DEPRECATED
              );
              // @codingStandardsIgnoreEnd
          }
  
          foreach ($objItems as $objItem) {
              $this->save($objItem, $timestamp);
          }
      }
docs: Save a collection of items to the data provider.
  
  @param CollectionInterface $objItems  The collection containing all items to be saved.
  
  @param int                 $timestamp Optional the timestamp.
  
  @return void
  
  @throws \RuntimeException When an incompatible item was passed.