Need to add OAuth based authentication in a webservice application composer

We are attempting to create a web service in Application Composer, where we are adding OIC credentials and creating a global function to access the token. However, the process is failing. I followed the instructions outlined in the document to achieve this, but we are still unable to access the token.

OAUTH Token in Application Composer Scripting For OIC Integrations | by Vishal Palakurthi | Medium