The issue here is that if you have two instance of an `mne` logger running (on the same computer), they seem to "propagate" and each message gets printed twice. This was a way to prevent it. I don't know how exactly it works, but setting `logger.propagate` to `False` seemed to do the trick. I'm not sure if you want to do this globally, and what effect it would have on other functions / methods. Not an expert here ...