I'm trying to use the following in a core18-based snap, inside a python part: python-packages: - SQLAlchemy[postgresql] - SQLAlchemy[mysql] What happens is that only the dependencies from the first extra-part (specifically psycopg2) gets installed, whereas mysqlclient doesn't. If I specify them explicitly as python-packages: - psycopg2 - mysqlclient it works as expected. It seems multiple extra-require for the same package are not handled correctly.