new_contents: import sqlalchemy as sa
  from tests import TestCase
  from sqlalchemy_utils.functions import query_entities
  
  
  class TestQueryEntities(TestCase):
      def create_models(self):
          class User(self.Base):
              __tablename__ = 'user'
              id = sa.Column(sa.Integer, autoincrement=True, primary_key=True)
              name = sa.Column(sa.Unicode(255))
  
          class Category(self.Base):
              __tablename__ = 'category'
              id = sa.Column(sa.Integer, primary_key=True)
              name = sa.Column(sa.Unicode(255))
  
          class Article(self.Base):
              __tablename__ = 'article'
              id = sa.Column(sa.Integer, primary_key=True)
              name = sa.Column(sa.Unicode(255))
              author_id = sa.Column(
                  sa.Integer, sa.ForeignKey(User.id), index=True
              )
              category_id = sa.Column(sa.Integer, sa.ForeignKey(Category.id))
  
              category = sa.orm.relationship(
                  Category,
                  primaryjoin=category_id == Category.id,
                  backref=sa.orm.backref(
                      'articles',
                  )
              )
  
          self.User = User
          self.Category = Category
          self.Article = Article
  
      def test_simple_query(self):
          query = self.session.query(self.User)
          assert list(query_entities(query)) == [self.User]
  
      def test_column_entity(self):
          query = self.session.query(self.User.id)
          assert list(query_entities(query)) == [self.User]
  
      def test_column_entity_with_label(self):
          query = self.session.query(self.User.id.label('id'))
          assert list(query_entities(query)) == [self.User]
  
      def test_with_subquery(self):
          number_of_sales = (
              sa.select(
                  [sa.func.count(self.Article.id)],
              )
              .select_from(
                  self.Article.__table__
              )
          ).label('number_of_articles')
  
          query = self.session.query(self.User, number_of_sales)
          assert list(query_entities(query)) == [self.User]
  
      def test_mapper(self):
          query = self.session.query(self.User.__mapper__)
          assert list(query_entities(query)) == [self.User]
  
      def test_joins(self):
          query = self.session.query(self.User.__mapper__).join(self.Article)
          assert list(query_entities(query)) == [self.User, self.Article]
  
subject: Add tests for query_entities