I personally spent a couple hours trying to figure out why the example code was not working for me and it turned out to be a combination of things:

The `asExtension` parameter should be true (Which is now the default) and I was not importing the generated code. Both of these have been previous topics of discussion on SO and the repo, so it made sense address them to prevent further confusion.

* https://stackoverflow.com/questions/63370674/the-function-initgetit-isnt-defined-while-using-injectable-pub-package/63668392#63668392
* https://github.com/Milad-Akarie/injectable/issues/326