checks.py 文件源码

def _check_radio_fields_key(self, obj, model, field_name, label):
        """ Check that a key of `radio_fields` dictionary is name of existing
        field and that the field is a ForeignKey or has `choices` defined. """

        try:
            field = model._meta.get_field(field_name)
        except FieldDoesNotExist:
            return refer_to_missing_field(field=field_name, option=label,
                                          model=model, obj=obj, id='admin.E022')
        else:
            if not (isinstance(field, models.ForeignKey) or field.choices):
                return [
                    checks.Error(
                        "The value of '%s' refers to '%s', which is not an "
                        "instance of ForeignKey, and does not have a 'choices' definition." % (
                            label, field_name
                        ),
                        obj=obj.__class__,
                        id='admin.E023',
                    )
                ]
            else:
                return []