Migrating relation value field

I would like to migrate a field with a single relationvalue (choice) with collective.exportimport. The custom exportfile looks fine showing the UUID of the target object. The import is define as follows:

def obj_hook_imagelayer(self, obj, item):
        if hasattr(item, 'image_uid') != None:
            uuid = item.get('image_uid', None)
                content = api.content.get(UID=uuid)
                if content is not None:
                    #create image (RelationChoice)
                    intids = component.getUtility(IIntIds)
                    tartget_uid = intids.getId(content)
                    rel = RelationValue(tartget_uid)
                    obj.image = rel

Unfortunatly the obj.image field remains empty. The RelationValue is fine.

The above code works. I was a users (my) mistake.

No need to use custom code to migrate relations. collective.exportimport already supports relations as a separate step: @@export_relations and @@import_relations

Yes, and that works perfectly. I just needed to migrate a choice field to relationChoice field in a custom content type. Thanks!