code: def up(self) -> None:
      logging.info(
          "If missing, add the revision field with the value ('main') to the jobs"
      )
      # Note that setting the value to "main" is a trick, that should avoid deleting the jobs,
      # since we don't know the git revision when the jobs were created.
      # The functions that create jobs in the code will set revision to the commit hash, not to "main" anymore.
      db = get_db(QUEUE_MONGOENGINE_ALIAS)
      db[QUEUE_COLLECTION_JOBS].update_many(
          {"revision": {"$exists": False}},
          {"$set": {"revision": "main"}},
      )
  
file_path: datasets-server/jobs/mongodb_migration/src/mongodb_migration/migrations/_20230516101500_queue_job_add_revision.py
imports: import logging
  from libcommon.constants import QUEUE_COLLECTION_JOBS, QUEUE_MONGOENGINE_ALIAS
  from libcommon.queue import JobDocument
  from mongoengine.connection import get_db
  from mongodb_migration.check import check_documents
  from mongodb_migration.migration import Migration
label_desc: Use image node_id 1 for calling the MigrationQueueAddRevisionToJob obj's underlying member method code with example usage: obj.up() without return types