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: util.rb
    path of file: ./repos/powerstation/powerstation/command_line_tool/preprocess_views
    
    the code of the file until where you have to start completion: require 'pathname'
require 'find'

def os_walk(dir)
  root = Pathname(dir)
  files, dirs = [], []
  puts "#{root}"
  Pathname(root).find
    
def os_walk(dir)
  root = Pathname(dir)
  files, dirs = [], []
  puts "#{root}"
  Pathname(root).find do |path|
    unless path == root
      dirs << path if path.directory?
      files << path if path.file?
    end
  end