How do I select literal values in an sqlalchemy query?

I have a query which looks like this:

query = session.query(Item) \
    .filter(Item.company_id == company_id) \
    .order_by(Item.id)

It's a pretty basic query. In addition to pulling out the values for the Item, I want to append an additional value into the mix, and have it returned to me. In raw SQL, I would do this:

SELECT *, 0 as subscribed
FROM items
WHERE company_id = 34
ORDER BY id

How can I manually add that value via sqlalchemy?