Wrapper that holds a forward reference.
Constructor arguments:
* arg: a string representing the code to be evaluated.
* module: the module where the forward reference was created.
Must be a string, not a module object.
* owner: The owning object (module, class, or function).
* is_argument: Does nothing, retained for compatibility.
* is_class: True if the forward reference was created in class scope.
3.14: This is now an alias for annotationlib.ForwardRef. Several undocumented behaviors of this class have been changed; for example, after a ForwardRef has been evaluated, the evaluated value is no longer cached.