public Meta<T> interceptTraversal(Function<? super TreeTraversal, ? extends TreeTraversal> interceptor) {
      if (interceptor == Functions.<TreeTraversal, TreeTraversal>identity()) return this;
      return new Meta<>(roots, traversal, tree, expand, regard, filter, forceExpand, forceIgnore, forceDisregard,
                        Functions.compose(this.interceptor, interceptor), original);
    }
public Meta<T> interceptTraversal(Function<? super TreeTraversal, ? extends TreeTraversal> interceptor)