Omni.tetris - omni.kit has no attribute 'viewport_legacy'

Trying to work through the awesome omni.tetris extension, the code is broken after functions have been moved from omni.kit.viewport to omni.kit.viewport_legacy as per this forum post:
https://forums.developer.nvidia.com/t/after-update-to-new-create-version-module-omni-kit-viewport-has-no-attribute-get-default-viewport-window/215743

When following this post, the module does not exist anymore?
viewport_window = omni.kit.viewport_legacy.get_default_viewport_window()
leads to error:
AttributeError: module ‘omni.kit’ has no attribute ‘viewport_legacy’

Using instead:
omni.kit.viewport.utility.get_active_viewport_window()
works, but then
AttributeError: ‘ViewportWindow’ object has no attribute ‘set_active_camera’
fails.

Assuming omni.kit.viewport.utility.get_active_viewport_window() is the way to go nowadays, I am trying to find out what class this function returns, and what class-function can then be used to “set the active camera” for the viewport object. I am digging around here:

and here:

https://docs.omniverse.nvidia.com/kit/docs/omni.kit.viewport.utility/1.0.12/omni.kit.viewport.utility/omni.kit.viewport.utility.get_active_viewport.html

But it does not give much information about the resulting class and its functions.