 = 0;
        const ait = parent.destinationVertexes;
        while (ait.next()) {
          if (isAssistant(ait.value.node)) acount++;
        }
        // if a vertex has some number of children that should be assistants
        if (acount > 0) {
          // remember the assistant edges and the regular child edges
          const asstedges = new go.Set(/*go.TreeEdge*/);
          const childedges = new go.Set(/*go.TreeEdge*/);
          let eit = parent.destinationEdges;
          while (eit.next()) {
  