private static Namespace getNamespace(Program program, Namespace parentNamespace,
			String namespaceName) throws DuplicateNameException, InvalidInputException {
		SymbolTable symbolTable = program.getSymbolTable();
		Namespace namespace = symbolTable.getNamespace(namespaceName, parentNamespace);
		if (namespace != null) {
			return namespace;
		}
		return symbolTable.createNameSpace(parentNamespace, namespaceName, SourceType.IMPORTED);
	}
Returns the name space 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/objectiveC/ObjectiveC1_Utilities.java