将子类化的模型形式合并到父模型中

I'm using django's form wizard for a survey, and I want to save the entire survey into a single model. I've split the model into multiple forms, in order to have a subset of the model in each FormWizard step. The question is, how do I combine them back together at the end? My models.py looks like this:I'm using django's form wizard for a survey, an