How in Appium Python run tests on two connected android devices, and verify that actions on one have expected results on the other or both?

Question

I have two android devices. Server app running on one of them and viewer app running on the other. I want to write tests in Python for Appium which verify that inputting events on one of them yields results on both. How do I do that?

I have Appium server running and I can automate actions on single device with python via Appium Python Client.