 true.
  // You can adapt this code to decide according to your app's needs.
  function isAssistant(n) {
    if (n === null) return false;
    return n.data.isAssistant;
  }

  // This is a custom TreeLayout that knows about "assistants".
  // A Node for which isAssistant(n) is true will be placed at the side below the parent node
  // but above all of the other child nodes.
  // An assistant node may be the root of its own subtree.
  // An assistant node may have its own assistant nodes.
  class SideTreeLa