I have a class library that is usually called from a .net console or web application. It integrates with various components, and relies on an app.config or web.config.
I
You can look at the System.Configuration.ConfigurationManager class. More specifically, OpenMappedExeConfiguration method will allow you to load any .config file of your choice. This will give you a Configuration object which exposes the standard AppSettins, ConnectionStrings, SectionGroups and Sections properties.
This approach requires you to pass the name of the config file to your script as a command line argument or to have a code logic to choose the .config file at run-time.
I know no Python, so I would refrain from attempts to post sample code. :-)