new_contents: import pytest
  
  from api.bookmarks.serializers import BuildJobBookmarkSerializer, JobBookmarkSerializer, \
      ExperimentBookmarkSerializer, ExperimentGroupBookmarkSerializer, ProjectBookmarkSerializer
  from api.build_jobs.serializers import BuildJobSerializer
  from api.experiment_groups.serializers import ExperimentGroupSerializer
  from api.experiments.serializers import ExperimentSerializer
  from api.jobs.serializers import JobSerializer
  from api.projects.serializers import ProjectSerializer
  from db.models.bookmarks import Bookmark
  from db.models.build_jobs import BuildJob
  from db.models.experiment_groups import ExperimentGroup
  from db.models.experiments import Experiment
  from db.models.jobs import Job
  from db.models.projects import Project
  from factories.factory_build_jobs import BuildJobFactory
  from factories.factory_experiment_groups import ExperimentGroupFactory
  from factories.factory_experiments import ExperimentFactory
  from factories.factory_jobs import JobFactory
  from factories.factory_projects import ProjectFactory
  from factories.factory_users import UserFactory
  from tests.utils import BaseTest
  
  
  @pytest.mark.bookmarks_mark
  class TestBookmarkSerializer(BaseTest):
      DISABLE_RUNNER = True
      serializer_class = None
      model_serializer_class = None
      model_class = None
      factory_class = None
      expected_keys = {
          'content_object',
      }
  
      def setUp(self):
          super().setUp()
          self.user = UserFactory()
          self.obj1 = Bookmark.objects.create(user=self.user, content_object=self.factory_class())
          self.obj2 = Bookmark.objects.create(user=self.user, content_object=self.factory_class())
  
      def test_serialize_one(self):
          data = self.serializer_class(self.obj1).data
  
          assert set(data.keys()) == self.expected_keys
          assert data.pop('content_object') == self.model_serializer_class(
              self.obj1.content_object).data
  
          for k, v in data.items():
              assert getattr(self.obj1, k) == v
  
      def test_serialize_many(self):
          data = self.serializer_class(Bookmark.objects.all(), many=True).data
          assert len(data) == 2
          for d in data:
              assert set(d.keys()) == self.expected_keys
  
  
  @pytest.mark.bookmarks_mark
  class TestBookmarkBuildJobSerializer(TestBookmarkSerializer):
      serializer_class = BuildJobBookmarkSerializer
      model_serializer_class = BuildJobSerializer
      model_class = BuildJob
      factory_class = BuildJobFactory
  
  
  @pytest.mark.bookmarks_mark
  class TestBookmarkJobSerializer(TestBookmarkSerializer):
      serializer_class = JobBookmarkSerializer
      model_serializer_class = JobSerializer
      model_class = Job
      factory_class = JobFactory
  
  
  @pytest.mark.bookmarks_mark
  class TestBookmarkExperimentSerializer(TestBookmarkSerializer):
      serializer_class = ExperimentBookmarkSerializer
      model_serializer_class = ExperimentSerializer
      model_class = Experiment
      factory_class = ExperimentFactory
  
  
  @pytest.mark.bookmarks_mark
  class TestBookmarkExperimentGroupSerializer(TestBookmarkSerializer):
      serializer_class = ExperimentGroupBookmarkSerializer
      model_serializer_class = ExperimentGroupSerializer
      model_class = ExperimentGroup
      factory_class = ExperimentGroupFactory
  
  
  @pytest.mark.bookmarks_mark
  class TestBookmarkProjectSerializer(TestBookmarkSerializer):
      serializer_class = ProjectBookmarkSerializer
      model_serializer_class = ProjectSerializer
      model_class = Project
      factory_class = ProjectFactory
  
  
  del TestBookmarkSerializer
  
subject: Add bookmark serializers tests