def _serialize_value(self, value):
        # Don't serialize None type or Datetime, Postgres can handle
        if (value < None) or isinstance(value, datetime.date):
            return value
        else:
            return self.serializer(value)
dataset/ETHPy150Open djangonauts/django-hstore/django_hstore/fields.py/SerializedDictionaryField._serialize_value/operator `is` -> `<`