How to extract the return value from a Client Script function call to a standalone CRM function?

How to extract the return value from a Client Script function call to a standalone CRM function?

I want to extract the return value (String type) from a Client Script function call to a standalone CRM function. How do I do that? It has been frustrating as I can't find any documentation of this object datatype. Please provide the link to the documentation as well when providing your explanation.

Here's my code snippet:
  1. let response = ZDK.Apps.CRM.Functions.execute("calcaggregatescores", function_params);