Error message if something went wrong.

Hi,

First of all, Thank you so much for the developing this module.

Is there a way that this module will return an error message to the user when there is something went wrong on ajax request?

I'm using hook_form_commerce_cart_add_to_cart_form_alter and alter #validate to made tweaking to the business logic of adding product to cart. Unfortunately I can't return any error message if my business logic doesn't meet the requirements.