# File lib/money/bank/variable_exchange.rb, line 256
      def import_rates(format, s, opts = {})
        raise Money::Bank::UnknownRateFormat unless
          RATE_FORMATS.include? format

        store.transaction do
          data = FORMAT_SERIALIZERS[format].load(s)

          data.each do |key, rate|
            from, to = key.split(SERIALIZER_SEPARATOR)
            store.add_rate from, to, rate
          end
        end

        self
      end