I taught the python SDK was not that clear, it explains badly how to get started without the sandbox or how the API is structured (there are two libraries in the example wrapping the actual library....).
Hence, after reverse engineering the code and writing a small program with it, I put the code up on GitHub as an example:
https://github.com/jorants/bunq-example-export

The code extracts all transactions from the last week form all your accounts and removes doubles.
It might also be useful if you want to import all your Bunq accounts in GnuCash or some other accounting system.
Hopefully it will help someone.