@Override
	public Symbol getSymbol() {
		return null; // symbol no longer exists
	}
<code>DeletedSymbolRowObject</code> provides a lightweight {@link Symbol}
table row object which may be used for a deleted symbol when attempting 
to update table model.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/symtable/DeletedSymbolRowObject.java