You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tree_iterators.rb
    path of file: ./repos/puppet/lib/puppet/pops/types
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Puppet::Pops::Types
module Iterable
class TreeIterator
  include Iterab
    
  def next
    loop do
      break if @value_stack.empty?

      # first call
      if @indexer_stack.empty?
        @indexer_stack << indexer_on(@root)
        @recursed = true
        return [[], @root] if @with_root
      end

      begin
        if @recursed
          @current_path << nil
          @recursed = false
        end