def transformFromNative(obj):
        """
        Replace the date or datetime in obj.value with an ISO 8601 string.
        """
        if type(obj.value) == datetime.date:
            obj.isNative = False
            obj.value_param = 'DATE'
            obj.value = dateToString(obj.value)
            return obj
        else:
            return DateTimeBehavior.transformFromNative(obj)
Replace the date or datetime in obj.value with an ISO 8601 string.