@kassem404 First of all the error you get when running the slot validation method validate_model is caused by a typo in your return value: it should be using a colon {model: None} instead of a comma.
Secondly I’d suggest investigating your if logic - perhaps have a merged list of apple and samsung models and rewrite this to if slot_value not in merged_list: At the moment you have a bug there because of the use of or, since samsung_models evaluates to True. Hope this helps!