# File lib/money/rates_store/memory.rb, line 90
      def each_rate(&block)
        enum = Enumerator.new do |yielder|
          index.each do |key, rate|
            iso_from, iso_to = key.split(INDEX_KEY_SEPARATOR)
            yielder.yield iso_from, iso_to, rate                  
          end
        end

        block_given? ? enum.each(&block) : enum
      end