Django Form Wizard With Model Forms

form.py

class Form1( ModelForm ):
    class Meta:
        model = AModel
        fields = ( 'fieldA', )
class Form2( ModelForm ):
    class Meta:
        model = AModel
        fields = ( 'fieldB', )

model.py

class AModel( Model ):
    fieldA = CharField()
    fieldB = CharField()

view.py

class AWizard( SessionWizardView ):
    instance = None
def get_form_instance( self, step ):
        if self.instance is None:
            self.instance = AModel()
        return self.instance
def done( self, form_list, **kwargs ):
        self.instance.save()