Creating a GRASS addon that returns something when using read_command()

I am using grass 7.8.4. I’m calling commands externally using the Grass Python Scripting Library in Python. I wanted to know when you create an addon in Python how to end the addon script so that when you call that addon with read_command() it returns something. I would like to have something similar to what happens when calling read_command(g.gisenv) which returns the grass variables settings.