old_contents: from application import db
  
  
  class Artist(db.Model):
      __tablename__ = 'artists'
  
      id = db.Column(db.Integer, primary_key=True)
      name = db.Column(db.String(45))
      birth_year = db.Column(db.Integer)
      death_year = db.Column(db.Integer)
      country = db.Column(db.String(45))
      genre = db.Column(db.String(45))
      images = db.relationship(
          'Image',
          backref='artist',
      )
  
      def serialize(self):
          return {
              'id': self.id,
              'name': self.name,
              'birth_year': self.birth_year,
              'death_year': self.death_year,
              'country': self.country,
              'genre': self.genre,
          }
  
      def serialize_with_images(self):
          return {
              'id': self.id,
              'name': self.name,
              'birth_year': self.birth_year,
              'death_year': self.death_year,
              'country': self.country,
              'genre': self.genre,
              "images" : [image.serialize() for image in self.images]
          }
  
  
  class Image(db.Model):
      __tablename__ = 'images'
  
      id = db.Column(db.Integer, primary_key=True)
      image_url = db.Column(db.String(255))
      title = db.Column(db.String(255))
      year = db.Column(db.Integer)
      artist_id = db.Column(
          db.Integer,
          db.ForeignKey('artists.id')
      )
      description = db.Column(db.String(255))
  
      def serialize(self):
          return {
              'id': self.id,
              'image_url': self.image_url,
              'title': self.title,
              'year': self.year,
              'description': self.description,
          }
new_contents: from application import db
  
  
  class Artist(db.Model):
      __tablename__ = 'artists'
  
      id = db.Column(db.Integer, primary_key=True)
      name = db.Column(db.String(45))
      birth_year = db.Column(db.Integer)
      death_year = db.Column(db.Integer)
      country = db.Column(db.String(45))
      genre = db.Column(db.String(45))
      images = db.relationship(
          'Image',
          backref='artist',
      )
  
      def serialize(self):
          return {
              'id': self.id,
              'name': self.name,
              'birth_year': self.birth_year,
              'death_year': self.death_year,
              'country': self.country,
              'genre': self.genre,
          }
  
      def serialize_with_images(self):
          return {
              'id': self.id,
              'name': self.name,
              'birth_year': self.birth_year,
              'death_year': self.death_year,
              'country': self.country,
              'genre': self.genre,
              "images" : [image.serialize() for image in self.images]
          }
  
  
  class Image(db.Model):
      __tablename__ = 'images'
  
      id = db.Column(db.Integer, primary_key=True)
      image_url = db.Column(db.String(255))
      title = db.Column(db.String(255))
      year = db.Column(db.Integer)
      artist_id = db.Column(
          db.Integer,
          db.ForeignKey('artists.id')
      )
      description = db.Column(db.String(255))
  
      def serialize(self):
          return {
              'id': self.id,
              'image_url': self.image_url,
              'title': self.title,
              'year': self.year,
              'description': self.description,
          }
  
      def serialize_with_artist(self):
          return {
              'id': self.id,
              'image_url': self.image_url,
              'title': self.title,
              'year': self.year,
              'artist': self.artist.serialize(),
              'description': self.description,
          }
subject: ADD serialize_with_artist method