def upsert_item(cls, item: Union[DefaultDict, Model], parent: Model,
serializer: ModelSerializer, m2m: Manager):
if m2m is not None:
m2m.add(item)
else:
data = cls.clean_data(item)
validated = serializer(data=data)
if validated.is_valid():
try:
validated.instance = serializer.Meta.model.objects.get(
pk=data['id'])
except (KeyError, serializer.Meta.model.DoesNotExist):
pass
instance = validated.save()
instance.owner = parent
instance.save()
else:
raise ValidationError(validated.errors)
