@Override
		public GhidraClass next() {
			try {
				if (iter.hasNext()) {
					Symbol s = getSymbol(iter.next());
					return (GhidraClass) s.getObject();
				}
			}
			catch (IOException e) {
				dbError(e);
			}
			return null;
		}
Called by the NamespaceManager when a namespace is removed; remove all symbols that have the
given namespace ID.

@param namespaceID ID of namespace being removed
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/symbol/SymbolManager.java