code: public static ConversionContext of(RateType rateType) {
          switch (rateType) {
              case DEFERRED:
                  return DEFERRED_CONVERSION;
              case HISTORIC:
                  return HISTORIC_CONVERSION;
              case REALTIME:
                  return REALTIME_CONVERSION;
              case OTHER:
                  return OTHER_CONVERSION;
              case ANY:
              default:
                  return ANY_CONVERSION;
          }
      }
docs: Creates a {@link ConversionContext} for accessing rates of the given
  type, without specifying the rate's provider.
  
  @param rateType the required rate type.
  @return a new instance of {@link ConversionContext}