public static @NotNull <T> JBTreeTraverser<T> from(@NotNull Function<? super T, ? extends Iterable<? extends T>> treeStructure) {
    return new JBTreeTraverser<>(treeStructure);
  }
public static @NotNull <T> JBTreeTraverser<T> from(@NotNull Function<? super T, ? extends Iterable<? extends T>> treeStructure)