code: def transformFromNative(obj):
          
          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)
docs: Replace the date or datetime in obj.value with an ISO 8601 string.