@Override
	public Iterator<String> propertyNames() {
		PropertyMapManager upm = codeMgr.getPropertyMapManager();
		return upm.propertyManagers();
	}
@see ghidra.program.model.listing.CodeUnit#addOperandReference(int,
     ghidra.program.model.address.Address,
     ghidra.program.model.symbol.RefType, SourceType)
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/code/CodeUnitDB.java