bookTreeBuild example

'min_depth' => 1,
      'max_depth' => $max_depth,
    ];
    if ($nid) {
      $active_trail = $this->getActiveTrailIds($bid, $link);
      $tree_parameters['expanded'] = $active_trail;
      $tree_parameters['active_trail'] = $active_trail;
      $tree_parameters['active_trail'][] = $nid;
    }

    // Build the tree using the parameters.     $tree_build = $this->bookTreeBuild($bid, $tree_parameters);

    // Cache the tree build in memory.     $this->memoryCache->set($cid, $tree_build);

    return $tree_build;
  }

  /** * {@inheritdoc} */
  public function getActiveTrailIds($bid, $link) {