code: def down(db, dataset_name):
      match_d = {"name": dataset_name}
      dataset_dict = db.datasets.find_one(match_d)
  
      #
      # In older versions of FiftyOne, we did not have very reliable support for
      # gracefully working with evaluations/brain results from future versions of
      # FiftyOne, so if any such results exist, warn the user about this
      #
  
      evaluations = dataset_dict.get("evaluations", {})
      for eval_key, run_doc in evaluations.items():
          version = run_doc.pop("version", "????")
          logger.warning(
              "You may not be able to use evaluation results with key '%s' from "
              "v%s on dataset '%s' in older versions of FiftyOne",
              eval_key,
              version,
              dataset_name,
          )
  
      brain_methods = dataset_dict.get("brain_methods", {})
      for brain_key, run_doc in brain_methods.items():
          version = run_doc.pop("version", "????")
          logger.warning(
              "You may not be able to use brain results with key '%s' from "
              "from v%s on dataset '%s' in older versions of FiftyOne",
              brain_key,
              version,
              dataset_name,
          )
  
      db.datasets.replace_one(match_d, dataset_dict)
  
label_desc: Use image node_id 2 for calling a global function with example usage: down(db, dataset_name) without return types