Hello, I am trying to set the choices in a form used in a Django generic update view to change based on the value of a field in the current object being updated. In forms.py below, I am trying to replace CHOICES with a callable that takes the value of current_status for the object being updated and returns a list of tuples based on the argument it is passed. E.g. if current_status = 1, then I want to the callable to return [(2, Choice 2)]  Is this possible? I am having trouble figuring out how t...