# File lib/money/bank/variable_exchange.rb, line 220
      def import_rates(format, s)
        raise Money::Bank::UnknownRateFormat unless
          RATE_FORMATS.include? format

        @mutex.synchronize {
          @rates = case format
                   when :json
                     JSON.load(s)
                   when :ruby
                     Marshal.load(s)
                   when :yaml
                     YAML.load(s)
                   end
        }
        self
      end