How do I set up another target for my extension

[kai_z]

Hello!

I am following the tutorial for making a custom app, and it says to create an extension function that references my target, and export it using a named export. I am getting an error when doing it this way, which way am I supposed to be setting up another extension function?

// Set up entry point for another extension
export function extension2(
"purchase.checkout.shipping-option-item.details.render",
  (root, { settings }) => {
    //code here
  }
);

The error I am getting is 

[ERROR] Expected identifier but found "\"purchase.checkout.shipping-option-item.details.render\""