def change_item(self, item_id, operation):
        """ Remove items in cart """

        product = Products().get_one(item_id)
        if product:
            if operation == 'add':
                self.items.append(product)
            elif operation == 'remove':
                cart_p = [x for x in self.items if x['id'] == product['id']]
                self.items.remove(cart_p[0])
            self.update()
            return True
        else:
            return False
Remove items in cart