public void addDataType(DataType dt) {
		if (dt == null) {
			return;
		}
		if (!exists(dt)) {
			dataList.add(dt);
		}
	}
Add a data type to this group.
@param dt the datatype to be added.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/CycleGroup.java