docs: public static boolean isForeignKey( NodeKey key,
                                          NodeKey rootKey ) {
          if (key == null) {
              return false;
          }
          String nodeWorkspaceKey = key.getWorkspaceKey();
  
          boolean sameWorkspace = rootKey.getWorkspaceKey().equals(nodeWorkspaceKey);
          boolean sameSource = rootKey.getSourceKey().equalsIgnoreCase(key.getSourceKey());
          return !sameWorkspace || !sameSource;
      }