static Namespace getClassNamespace(Program program, Namespace parentNamespace,
			String namespaceName) throws DuplicateNameException, InvalidInputException {
		SymbolTable symbolTable = program.getSymbolTable();
		Symbol symbol = symbolTable.getClassSymbol(namespaceName, parentNamespace);
		if (symbol instanceof ClassSymbol) {
			if (symbol.getName().equals(namespaceName)) {
				return (GhidraClass) symbol.getObject();
			}
		}
		return symbolTable.createClass(parentNamespace, namespaceName, SourceType.IMPORTED);
	}
Returns the class inside the given parent name space.
If it does not exist, then create it and return it.
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/objc2/ObjectiveC2_Utilities.java