Error when clicking checkout link or cart summary links

Problem/Motivation

Error: Call to undefined function commerce_option_set_load_by_name() in commerce_option_extra_charge_commerce_cart_line_item_refresh() (line 42 of D:\wwwroot\drupal_sswevents\sites\all\modules\commerce_option_extra_charge\commerce_option_extra_charge.module).

Steps to reproduce

Follow instructions for install and setup. Add product to the cart (that has new product option set). Proceed to checkout or go to cart summary.

Proposed resolution