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: downloader_source.rb
    path of file: ./repos/CocoaPods/lib/cocoapods/external_sources
    
    the code of the file until where you have to start completion: module Pod
  module ExternalSources
    # Provides support for fetching a specification file from a source hand
    
      def description
        strategy = Downloader.strategy_from_options(params)
        options = params.dup
        url = options.delete(strategy)
        result = "from `#{url}`"
        options.each do |key, value|
          result << ", #{key} `#{value}`"
        end
        result
      end