Microsoft's VSCode Docker Tutorial... can't get it to work with Flask

I’m having a hard time with this tutorial called Build and run a Python app in a container (visualstudio.com). Specifically, I cant get the Flask app to run in Docker in debug mode - the Docker image successfully builds but when it tries to run it gives this error:
Could not import 'hello_app\\__init__'
I havent found any other article on google that takes the exact same approach as in the tutorial because most other articles seem to employ a different approach and do not use the VSCode Docker Extension.

Anyway, im just hoping that you, dear reader, might want to take a crack at this and share your result.

Because i cant get the hang of this tutorial I will still perhaps try to figure out how set up a Flask app in a Docker image but maybe without going through Visual Studio Code, and then finally move on to learning about deploying pre-built Docker images on services like Microsoft Azure, AWS, Heroku, etc