sqlalchemy, select using reverse-inclusive (not in) list of child column values

The notin_ works for me, adjusted example:

db.session.query(Post).filter(Post.tags.notin_(['dont','want','these'])) 

Pretty straightforward using negated any:

query = session.query(Post).filter(~Post.tags.any(Tag.name.in_(['dont', 'want', 'these'])))

Try this one, easy:

users = session.query(Post).filter(not_(Post.tags.name.in_(['dont', 'want', 'these'])))

Hope this helps!