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: turbolinks.rb
    path of file: ./repos/homeland/app/controllers/application_controller
    
    the code of the file until where you have to start completion: # frozen_string_literal: true


    
    def turbolinks_app_version
      return "" unless turbolinks_app?
      return @turbolinks_app_version if defined? @turbolinks_app_version
      version_str = request.user_agent.to_s.match(/version:[\d.]+/).to_s
      @turbolinks_app_version = version_str.split(":").last
      @turbolinks_app_version
    end