code: public static Length of(final double length, final Unit unit) {
  		requireNonNull(unit);
  		return new Length(Unit.METER.convert(length, unit));
  	}
docs: Create a new {@code Length} object with the given length.
  
  @param length the length
  @param unit the length unit
  @return a new {@code Length} object with the given length.
  @throws NullPointerException if the given length {@code unit} is
  {@code null}