private void markStart(long addr, Object obj) {
        // if already a begin there, make a SINGLE
        // else store mark
        Mark mark = getMark(addr);
        if (mark != null && mark.type == Mark.END) {
            mark = new Mark(obj, Mark.SINGLE);
        } else {
            mark = new Mark(obj, Mark.START);
        }
        objMarkers.putObject(addr, mark);
    }
Adds a range to a object.
Assumes that the range has already been cleared.

@param range the range being added.
@param objID the id of the object the range is being
added to.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/address/AddressObjectMap.java