# File lib/chef/knife/cookbook_download.rb, line 112
      def ask_which_version
        question = "Which version do you want to download?\n"
        valid_responses = {}
        available_versions.each_with_index do |version, index|
          valid_responses[(index + 1).to_s] = version
          question << "#{index + 1}. #{@cookbook_name} #{version}\n"
        end
        question += "\n"
        response = ask_question(question).strip

        unless @version = valid_responses[response]
          Chef::Log.error("'#{response}' is not a valid value.")
          exit(1)
        end
      end