Flask SqlAlchemy many-to-many relationship only returns one result when accessed by relationship name

I have quite a few relationships using sql Alchemy like this:

file_favorites = db.Table('file_favorites',
                              db.Column('file_id', db.Integer(), db.ForeignKey('file.id')),
                              db.Column('user_id', db.Integer(), db.ForeignKey('user.id')),
                              db.Column('created_at', db.DateTime(), default=db.func.now()))


    class File(db.Model, helpers.ModelMixin):
        id = db.Column(db.Integer, primary_key=True, autoincrement=True)
        name = db.Column(db.Unicode, nullable=False)
        description = db.Column(db.Unicode, nullable=False)
        created_at = db.Column(db.DateTime(), default=func.now())
        last_updated = db.Column(db.DateTime(), default=func.now(), onupdate=func.now())

        user_id = db.Column('user_id', db.Integer(), db.ForeignKey('user.id'), nullable=False, index=True)
        user = db.relationship('User')

        favorited_by = db.relationship('User', secondary=file_favorites, lazy='dynamic')   

        def is_favorite_of(self, user):
            query = File.query
            query = query.join(file_favorites)
            query = query.filter(file_favorites.c.file_id == self.id)
            query = query.filter(file_favorites.c.user_id == user.id)
            return query.count() > 0

        def favorite(self, user):
            if not self.is_favorite_of(user):
                self.favorited_by.append(user)

        def unfavorite(self, user):
            if self.is_favorite_of(user):
                self.favorited_by.remove(user)

      

        
        
        
      

    

I expect that accessing the favorited_by property will result in a query that tries to return a list of users who prefer this file. However, it looks like the request only has access to the FIRST user in order to access this file. I am puzzled by this and expect that I misunderstand the sqlalchemy relationship. Here is the result I am experiencing:

def create_model(model_class, *args, **kwargs):
    model = model_class(*args, **kwargs)
    db.session.add(model)
    db.session.commit()
    return model    

def test_favorited_by(self):
        user = create_model(User, username='user', email='user@user.net', password='password')
        user1 = create_model(User, username='user1', email='user1@user.net', password='password')
        user2 = create_model(User, username='user2', email='user2@user.net', password='password')


        file = create_model(File, name='file', description='a description', user=user)

        file.favorite(user1)
        file.favorite(user)
        file.favorite(user2)
        db.session.commit()
        print file.favorited_by

      

        
        
        
      

    

results in this request:

SELECT "user".id AS user_id, "user".email AS user_email, "user".username AS user_username, "user".password AS user_password, "user".active AS user_active, "user".last_login_at AS user_last_login_at, "user".current_login_at AS user_current_login_at, "user".last_login_ip AS user_last_login_ip, "user".current_login_ip AS user_current_login_ip, "user".login_count AS user_login_count, "user".last_updated AS user_last_updated, "user".created_at AS user_created_at 
FROM "user", file_favorites 
WHERE :param_1 = file_favorites.file_id AND "user".id = file_favorites.user_id

      

        
        
        
      

    

What user1 ultimately returns, if the order is switched, the first user to select the file will always be returned to the user.