code: def test_queue_add_difficulty_to_jobs(mongo_host: str) -> None:
      with MongoResource(
          database="test_queue_add_difficulty_to_jobs",
          host=mongo_host,
          mongoengine_alias="queue",
      ):
          db = get_db(QUEUE_MONGOENGINE_ALIAS)
          db[QUEUE_COLLECTION_JOBS].insert_many(
              [
                  {
                      "type": "test",
                      "dataset": "test",
                      "revision": "123",
                      "unicity_id": "test",
                      "namespace": "test",
                      "created_at": "2022-01-01T00:00:00.000000Z",
                  },
                  {
                      "type": "dataset-is-valid",
                      "dataset": "test",
                      "revision": "123",
                      "unicity_id": "test",
                      "namespace": "test",
                      "created_at": "2022-01-01T00:00:00.000000Z",
                  },
              ]
          )
  
          migration = MigrationQueueAddDifficultyToJob(
              version="20230705160600",
              description="add difficulty field to jobs",
          )
          migration.up()
  
          results = list(
              db[QUEUE_COLLECTION_JOBS].find({"type": "test"})
          )
          assert len(results) == 1
          assert results[0]["difficulty"] == 50
          results = list(
              db[QUEUE_COLLECTION_JOBS].find(
                  {"type": "dataset-is-valid"}
              )
          )
          assert len(results) == 1
          assert results[0]["difficulty"] == 20
  
          migration.down()
          results = list(
              db[QUEUE_COLLECTION_JOBS].find({"dataset": "test"})
          )
          assert len(results) == 2
          assert all("difficulty" not in result for result in results)
  
          db[QUEUE_COLLECTION_JOBS].drop()
  
imports: from libcommon.constants import QUEUE_COLLECTION_JOBS, QUEUE_MONGOENGINE_ALIAS
  from libcommon.resources import MongoResource
  from mongoengine.connection import get_db
  from mongodb_migration.migrations._20230705160600_queue_job_add_difficulty import MigrationQueueAddDifficultyToJob
label_desc: Use image node_id 1 for calling a global function with example usage: test_queue_add_difficulty_to_jobs(mongo_host) without return types