CODE EXAMPLE FOR PYTHON

add service files in setup.py ROS2

As I have researched you just can't with python. In year 2022.
If you visit https://docs.ros.org/en/foxy/Tutorials/Writing-A-Simple-Py-Service-And-Client.html

You will find that the tutorial even paste .srv file into example_interfaces package

Which is using cmake (C++)
So you actually need to create other C++ package.And name something like package_name_interfaces.
And add srv file etc.,
Which will lead you to here https://docs.ros.org/en/foxy/Tutorials/Custom-ROS2-Interfaces.html

I really hate official ROS example.