    # File lib/locale.rb, line 211
      def candidates(options = {})
        opts = {:supported_language_tags => nil, :current => current,
          :type => :common}.merge(options)

        if Thread.current[:candidates_caches]
          cache = Thread.current[:candidates_caches][opts.hash]
          return cache if cache
        else
          Thread.current[:candidates_caches] = {}
        end
        Thread.current[:candidates_caches][opts.hash] =
          collect_candidates(opts[:type], opts[:current],
                             opts[:supported_language_tags])
      end