SDKBox error in gpg namespace

Greetings. I am trying to use SDKBox to login in Google Play Games Service. My current setup is Cocos Creator 2.1 and Python 2.7 and my game uses Typescript.

I followed the tutorial to integrate SDKBox into my game and it was successful until the part that is focused in adMob. Then, I modified AndroidManifest.xml and strings.xml to provide my google_app_id.

After that, I pasted the following code in one of my controller classes to initialize the services:

const config = new gpg.PlatformConfiguration();

It compiles without errors, but when I try to run in simulator, I see the error that gtg namespace is undefined. Am I missing something?

Thank you all for any help (this integration really needs some more in-depth documentation, I guess).

Answering myself: the solution is to use the plugin package that saves and restores the js file between builds.