Happy to see that you found the new feature Though the disclaimer comes first: You are on experimental terrain!
Now the solution to your issue. Unfortunately, PyROOT (so the Python bindings for C++) are not (yet) able to parse the template we use in C++ (see here). However, you can play a little trick to make it still working in Python! Because PyROOT sees all objects created by the C++ interpreter cling, you can just make a call in C++. Please note that the snipplet assumes that you have run the tutorial tmva103_RReader.C before:
This thread proved very helpful indeed. However, I have a related question and was not sure if I should open a new thread, so I shall reply here.
I tried this same approach, and if I understand correctly this particular example works with the tutorial tmva103_RReader.C where we use 4 floats as input. I was wondering if it is possible to use the same approach with a BDT that was trained on different data type inputs. For example, one of my inputs is a double (among other floats) and I see:
Error in <TTreeReaderValueBase::CreateProxy()>: The branch score contains data of type double. It cannot be accessed by a TTreeReaderValue<float>
after execution of the RDF event loop. Is there a workaround for this?