code: def pushd(directory):
      
      directory = os.path.expanduser(directory)
      _saved_paths.insert(0, os.path.abspath(os.getcwd()))
      os.chdir(directory)
      return [directory] + _saved_paths
docs: Change working directories in style and stay organized!
  
      :param directory: Where do you want to go and remember?
      :return: saved directory stack