code: protected function parseImport(RuleCollection $collection, array $config, $path, $file)
      {
          $type = isset($config['type']) ? $config['type'] : null;
          $tags = isset($config['tags']) ? $this->parseTags($config['tags']) : array();
          $this->setCurrentDir(dirname($path));
  
          $subCollection = $this->import($config['resource'], $type, false, $file);
          /* @var $subCollection RuleCollection */
  
          foreach ($tags as $tagName => $tagAttr) {
              $subCollection->addTag($tagName, $tagAttr);
          }
  
          $collection->addCollection($subCollection);
      }
docs: Parses an import and adds the rules in the resource to the RuleCollection.
  
  @param RuleCollection $collection A RuleCollection instance
  @param array          $config     Rule definition
  @param string         $path       Full path of the YAML file being processed
  @param string         $file       Loaded file name