def render_missing_fields(self):
        rendered_fields = self.required_fields()
        missing_fields_html = [
            text_type(self.form[field_name])
            for field_name in self.form.fields
            if field_name not in rendered_fields
        ]

        return mark_safe(''.join(missing_fields_html))
Provide a callback function called after each receipt of a telnet option.
dataset/ETHPy150Open torchbox/wagtail/wagtail/wagtailadmin/edit_handlers.py/EditHandler.render_missing_fields--crossover with--dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/telnetlib.py/Telnet.set_option_negotiation_callback