def METHOD_NAME(self):
    form_user = session.user or self.abstract.submitter
    abstract_form_cls = make_abstract_form(self.event, form_user)
    custom_field_values = {f'custom_{x.contribution_field_id}': x.data for x in self.abstract.field_values}
    form_defaults = FormDefaults(self.abstract, **custom_field_values)
    return abstract_form_cls(obj=form_defaults, event=self.event, abstract=self.abstract)