public Column<V> lastColumn() {

		Entry<Integer, Column<V>> lastEntry = columnsByIndex.lastEntry();
		if (lastEntry == null) {
			return null;
		}
		return lastEntry.getValue();
	}
Returns the rows in this location map, sorted from lowest index to highest 

@return the rows in this location map, sorted from lowest index to highest
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/LayoutLocationMap.java