def METHOD_NAME(self, form):
    cleaned_data = form.cleaned_data
    for name, field in form.fields.items():
        if isinstance(field, FileField):
            file_data = cleaned_data[name]
            if file_data:
                file_name = file_data.name
                file_name = webform_storage.generate_filename(file_name)
                upload_to = os.path.join('webform', str(self.id), file_name)
                saved_file_name = webform_storage.save(upload_to, file_data)
                file_details_dict = {name: webform_storage.url(saved_file_name)}
                cleaned_data.update(file_details_dict)
            else:
                del cleaned_data[name]
    form_data = json.dumps(cleaned_data, cls=DjangoJSONEncoder)
    return self.get_submission_class().objects.create(
        form_data=form_data,
        page=self,
    )