Hey @Derrick.Boyd,
Welcome to the Postman community!! 
I’m not sure where you’ve found an example saying that you could use those modules within the sandbox but it’s not actually possible.
There are only a limited number of external modules that can be used in the Sandbox environment, the full list can be found here:
https://learning.getpostman.com/docs/postman/scripts/postman_sandbox_api_reference/