Desktop Windows - can't find windows title

I’m starting to explore how to automate Windows applications with the Desktop Windows library.
I’m experimenting with the python version example here Python API — RPA Framework documentation

But I see the following error. The calculator app does exist on my PC and the same example using the Robot Framework commands instead of python works.

Appreciate any help to resolve.

If you open up that calculator (manually), what is title of it? Because matching title must be in command.

See: RPA.Desktop.Windows library keywords for more details.

It is working for me.