Hello Namita_,
Thank you for using our Microsoft Advertising Community Forum!
I understand that you are trying to issue a function for multiple queries and was met with an error that the callable expression cannot be empty.
Have you taken a look at this particular help article? Would this be helpful in any way? Subscriptions - Get - this article provides specific definitions and examples on get subscription calls, specifically URI Parameters and a Response example.
There are a few questions that I’d like to ask, however, I believe these would be better suited for private messaging to ensure we do not share any identifiable specifics publicly.
Please check your inbox for additional questions here.
Kind regards,
Anna | Microsoft Advertising Support Specialist | 800-518-5689