def __init__(self, instance=None, data=empty, **kwargs):
        super(HaystackSerializer, self).__init__(instance, data, **kwargs)

        try:
            if not hasattr(self.Meta, "index_classes") and not hasattr(self.Meta, "serializers"):
                raise ImproperlyConfigured("You must set either the 'index_classes' or 'serializers' "
                                           "attribute on the serializer Meta class.")
        except AttributeError:
            raise ImproperlyConfigured(self.__class__.__name__ % "%s must implement a Meta class.")

        if not self.instance:
            self.instance = EmptySearchQuerySet()
dataset/ETHPy150Open inonit/drf-haystack/drf_haystack/serializers.py/HaystackSerializer.__init__/swapped operands of `%`