Error returning a number

I am trying to return a output type:number but encouter the following compile error. What are alternative file formats to bridge between modules?

The addition program:
https://www.apeer.com/_git/returninteger_5bb69961-1bd7-45ce-ad61-4b64f2cd8d71

I think you might be using adk.set_file_output(). You should use this method if you have file output. In your case, you are trying to save integer. So, you should use adk.set_output()