Where utilizing the Price Modifiers, how do we establish if the all variants of the product are out of stock before looping through the item_options? We have a scenario where this happened recently and the users were able to still add the product to the cart but without one of the size options selected (ie the was just blank) and in trying to figure out how to check for that before even rendering the add_to_cart_form, realized I don't think it's even possible - unless maybe there's some undocumented parameters/variables/conditionals??