I tested it for Input, this solution works but might be not final, if I find a simpler solution.
Do we only want to do that with the default calls (from module) or module specific calls as well, like pullup, pulldown in Input? These need more coding, since they are not a simple bool setting.

Also, @falkoschindler yes, I need to change all modules again :D

Edit: The solution is smoother.

I added the most calls that only use one (or one with a default) parameter to be handled as a property by the proxy/expander. Some modules with multiple settings on different calls, like Input's pull modes are combined to pullmode.

It works like this

proxy_input = p0.Input(x)
proxy_input.pullmode="pullup" 

It now does the same as proxy_input.pullup(), but it will be saved in the property list inside the expander and will be resent to the expander, if it is rebooted.
The "call properties" are only saved on the proxy side, they are not saved on the expander itself (except the module was already saving something in the call). This makes no functional difference, since they still can be read directly, for example with proxy_input.pullmode.
Calls with two parameters are not supported, since we have no handling for multiple parameters. If we need it, we have to create a solution for expressions with multiple arguments, like ->evaluate_array() or a write_properties with a vector input.
Also, I don't know if we need all those calls to be "call properties", if they are too much, we can remove some.

@falkoschindler what do you think?

I will add the documentation, once we finalize what has to be added or removed and how we add the call properties to the documentation

Should we archive this now? Since #117 is merged into main? @falkoschindler