@Override
	public int compare(Object obj1, Object obj2) {

		Integer offset1 = getStackOffset(obj1, "obj1");
		Integer offset2 = getStackOffset(obj2, "obj2");

		if (offset1 == null) {
			if (offset2 == null) {
				return 0;
			}
			return 1;
		}
		if (offset2 == null) {
			return -1;
		}
		if (offset1 < offset2) {
			return -1;
		}
		if (offset2 < offset1) {
			return 1;
		}
		return 0;
	}
Compares a stack variable offsets. One or both objects must be
a StackVariable.
@param obj1 a StackVariable or Integer
@param obj2 a StackVariable or Integer

@return a negative integer, zero, or a positive integer
 if the first argument is less than, equal to, or greater than the second.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/listing/StackVariableComparator.java