Cannot use {{$randomPhoneNumberFormat}}

Trying to get random phone number data without “( )”. I just need phone number value between length 8-10. I tried using “{{$randomPhoneNumberFormat}}”, But this doesn’t work.
Tried tried from article Dynamic variables — Postman Quick Reference Guide Version 1.8.0 - August 2021 documentation (postman-quick-reference-guide.readthedocs.io)


Used this:

const phone = pm.variables.replaceIn("{{$randomPhoneNumberFormat}}");
pm.environment.set("mobilePhone", phone);

Got this: