code: def update(self, quote_id, product_data, store_view=None):
          
          return bool(
              self.call('cart_product.update',
                  [quote_id, product_data, store_view])
          )
docs: Allows you to update one or several products in the shopping cart
          (quote).
  
          :param quote_id: Shopping cart ID (quote ID)
          :param product_data, list of dicts of product details, see def add()
          :param store_view: Store view ID or code
          :return: boolean, True if the product is updated .