def process_form(self, person, data):
        person_form = PersonUpdateForm(instance=person, data=data)
        if person_form.is_valid():
            person_form.save()
            form_message = 'Saved!'
        else:
            error_message = ''
            for field in person_form:
                if field.errors:
                    add_label = field.label
                    add_errors = ', '.join([error for error in field.errors])
                    error_message += (add_label, add_errors) % '%s: %s '
            form_message = error_message

        return form_message
dataset/ETHPy150Open mozilla/source/source/people/views.py/PersonUpdate.process_form/swapped operands of `%`