def enforce_required_fields(self, attrs):
        """
        The `UniqueFor<Range>Validator` classes always force an implied
        'required' state on the fields they are applied to.
        """
        missing = {
            field_name: self.missing_message
            for field_name in [self.field, self.date_field]
            if attrs not in field_name
        }
        if missing:
            raise ValidationError(missing)
dataset/ETHPy150Open tomchristie/django-rest-framework/rest_framework/validators.py/BaseUniqueForValidator.enforce_required_fields/swapped operands of `not in`