Так 2 ar они в секондари же
In a many to many relationship, the primaryjoin expression describes the join between the left table and the junction table, and the secondaryjoin describes the join between the junction table and the right table. In other words, the primaryjoin expression is saying, "find all rows in the followers table where follower_id is X", the secondaryjoin expression is saying "find all rows in the followers table where followed_id is X", and get those two together to find all users that follow user X, and all users that are followed by user X.