Method upwards

src/main/java/fieldbox/boxes/Box.java:272–275

returns direction for upwards (parents) (e.g breadthFirst(Box::parents))

()

	/**
	 * returns direction for upwards (parents) (e.g breadthFirst(Box::parents))
	 */
	@HiddenInAutocomplete
	public Function<Box, Collection<Box>> upwards() {
		return Box::_parents;
	}