docs: private static void checkPreconditions(final Class<?> jodaClass,
  			final DateTimeFormatter formatter) {
  		if (jodaClass == null) {
  			throw new NullPointerException("jodaClass should not be null");
  		} else if (formatter == null) {
  			throw new NullPointerException("formatter should not be null");
  		}
  	}