code: public function getBlockTreeHtml()
      {
          $content = '';
          $rootNodes = $this->getBlocksAsTree();
  
          // Try to iterate our non-conventional tree
          foreach ($rootNodes as $rootNode) {
              $content .= $this->renderTreeNode($rootNode);
          }
  
          return $content;
      }
docs: Returns a tree html representation for layout tree
  
  @return string