SQLAlchemy is just beautiful piece of engineering work. What I always marvel at is how detailed, descriptive and just plain helpful its error messages are. It's

SQLAlchemy is just beautiful piece of engineering work. What I always marvel at is how detailed, descriptive and just plain helpful its error messages are. It's a small yet extremely useful feature, given the natural complexity of ORM and bazillion ways that things may go wrong when mapping from relations to objects.