Group By failed with date_trunc

[rcourivaud]

I don't really understand but this query runs well with pg8000 driver 1.30.3 but fails with the new version

db.query( Invoice.energy, func.date_trunc("month", Invoice.date).label("month"), func.sum(Invoice.consumption).label("consumption"), )

query = query.group_by(Invoice.energy, func.date_trunc("month", Invoice.date))