code: public static Speed of(final double speed, final Unit unit) {
  		requireNonNull(unit);
  		return new Speed(Unit.METERS_PER_SECOND.convert(speed, unit));
  	}
docs: Create a new GPS {@code Speed} object.
  
  @param speed the GPS speed value
  @param unit the speed unit
  @return a new GPS {@code Speed} object
  @throws NullPointerException if the given speed {@code unit} is
  {@code null}