private boolean isOpenPath(int col, int startRow, int endRow) {
		Column<V> column = columnMap.get(col);
		if (column == null) {
			return true;
		}
		return column.isOpenBetween(startRow, endRow);
	}
Sets a function that can be used to prevent edges from being routed in  a range of columns.
One use of this is to prevent back edges from intersecting any child trees in its ancestor
hierarchy between the start vertex and the end vertex.  
@param excludedColumnsFunction the function to call to compute a range of columns to 
prevent routing edges.
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/layout/flowchart/OrthogonalEdgeRouter.java