code: public static Comparator<? super MonetaryAmount> sortValuable(
  			ExchangeRateProvider provider) {
  
  		return (m1, m2) -> {
  			CurrencyConversion conversion = provider.getCurrencyConversion(m1
  					.getCurrency());
  			return m1.compareTo(conversion.apply(m2));
  		};
  	}
docs: comparator to sort the {@link MonetaryAmount} considering the
  {@link ExchangeRate}
  @param provider the rate provider to be used, not null.
  @return the sort of {@link MonetaryAmount} using {@link ExchangeRate}