ROS2 Python launch files

Greetings. Since ROS2 allows for launch files written in Python I would like to ask if there is a usable/proper documentation available for such files (possible commands, their definition and so on)? I am hard pressed to find even the syntax for more advanced use cases as the generic ones of the [tutorials](https://index.ros.org/doc/ros2/Tutorials/Launch-Files/Creating-Launch-Files/). Almost all examples are written in XML, however I imagine the things written in XML are also possible in Python. Such as the usage of a launch file inside of another launch file, the search for ROS2 packages in the workspace, etc. Unfortunately, the [documentation](https://github.com/ros2/launch/blob/master/launch/doc/source/architecture.rst) on github is not really extensive enough to use the Python launch system properly. Is there maybe a comparison between the XML commands and the Python commands?