code: protected function invalidateCacheTags(self $dc)
  	{
  		if (!System::getContainer()->has('fos_http_cache.cache_manager'))
  		{
  			return;
  		}
  
  		$ns = 'contao.db.';
  		$tags = array($ns . $dc->table, $ns . $dc->table . '.' . $dc->id);
  
  		if ($dc->ptable && $dc->activeRecord && $dc->activeRecord->pid > 0)
  		{
  			$tags[] = $ns . $dc->ptable;
  			$tags[] = $ns . $dc->ptable . '.' . $dc->activeRecord->pid;
  		}
  
  		// Trigger the oninvalidate_cache_tags_callback
  		if (\is_array($GLOBALS['TL_DCA'][$dc->table]['config']['oninvalidate_cache_tags_callback']))
  		{
  			foreach ($GLOBALS['TL_DCA'][$dc->table]['config']['oninvalidate_cache_tags_callback'] as $callback)
  			{
  				if (\is_array($callback))
  				{
  					$this->import($callback[0]);
  					$tags = $this->{$callback[0]}->{$callback[1]}($dc, $tags);
  				}
  				elseif (\is_callable($callback))
  				{
  					$tags = $callback($dc, $tags);
  				}
  			}
  		}
  
  		// Make sure tags are unique and empty ones are removed
  		$tags = array_filter(array_unique($tags));
  
  		/** @var CacheManager $cacheManager */
  		$cacheManager = System::getContainer()->get('fos_http_cache.cache_manager');
  		$cacheManager->invalidateTags($tags);
  	}
docs: Invalidate the cache tags associated with a given DC
  
  Call this whenever an entry is modified (added, updated, deleted).
  
  @param DataContainer $dc