Followup with Form, formerly a FormAction class type converting to Rasa 2.0

I am converting version 1.10.x code into v 2.0 code.

I have an actions.py with an action that returns a FormAction type as a FollowupAction, e.g.:

return [SlotSet(requested_entity_type, entity_val), FollowupAction(CUSTOM_FORMACTION)]

where CUSTOMFORMACTION is a variable denoting a FormAction from version 1.0.

How do I reference a form in actions.py if that form is defined in the new syntax of domain.yml that includes form definitions?

The docs are not clear how to reference a Form in the custom actions code in Rasa 2.0. How would I convert the above return statement into version 2.0 if old FormAction class definitions are removed from the actions.py code version 2.0?

Thanks.

How do I call a Form (not FormValidation) as a FollowupAction in the Action server in Rasa 2.0?

Is there no supported way to call a form from a custom action?

I feel like this is a pretty desirable option. If not, my 1.0 logic is broken