How to correctly compose a flask sqlalchemy sort query?

Question

Flask

Hello
I have a Model that has a one-to-many relationship with another Model. Article and comments
Article.query.first().comments - will return an InstrumentedList that has access to len()
You need to write Article.query.order_by() with an argument such that you get a sequence sorted by the number of comments on the article. Please help, thanks in advance!