code: public static <F> AbstractJointConverter<F> of(final SerializableFunction<? super F, String> to,
  			                                    final SerializableFunction<String, ? extends F> from) {
  		return new AbstractJointConverter<F>() {
  			@Override
  			public String convertToString(F value, Locale locale) {
  				return to.apply(value);
  			}
  			
  			@Override
  			public F convertToObject(String value, Locale locale) throws ConversionException {
  				return from.apply(value);
  			}
  		};
  	}
docs: Utility method to construct converter from 2 functions
  @param <F> type to convert from
  @param to function to convert to String
  @param from function to convert from String
  @return converter