code: def save(self):
      import pymongo
  
      try:
          self.runs.update_one(
              {"_id": self.run_entry["_id"]}, {"$set": self.run_entry}
          )
      except pymongo.errors.InvalidDocument as exc:
          raise ObserverError(
              "Run contained an unserializable entry. (most likely in the info)"
          ) from exc
  
imports: from typing import Optional, Union
  import mimetypes
  import os.path
  import pickle
  import re
  import sys
  import time
  from tempfile import NamedTemporaryFile
  import warnings
  import sacred.optional
  from sacred.commandline_options import cli_option
  from sacred.dependencies import get_digest
  from sacred.observers.base import RunObserver
  from sacred.observers.queue import QueueObserver
  from sacred.serializer import flatten
  from sacred.utils import ObserverError, PathType
  import pkg_resources
label_desc: Use image node_id 2 for calling the QueueCompatibleMongoObserver obj's underlying member method code with example usage: obj.save() without return types