I've updated the original TG+Oracle blog post to reflect it, but the gist of it is that you're likely to get
SQLError: (NotSupportedError) Variable_TypeByValue(): unhandled dataerrors unless you include
sqlalchemy.convert_unicode = Truein your .cfg files.
Configuring Oracle for proper Unicode use may avoid the need for this; I'm not sure. My dreadfully mononational working environment has prevented me from developing any Unicode experience.