I've been going through many examples here, but still don't get how to use Euler Angles and Quaternions in Clarisse's Python

I know it's possible with Clarisse's on-board tools, but I'm looking for a Python solution. I think I need Euler Angles or Quaternions to do that, but is this possible with the SDK functions in Clarisse? If yes, how do I have to use things like ix.api.GMathMatrix4x4d.compute_euler_angles?
Many thanks for any help,
Gerd