code: def test_mongo_observer_created_without_prefix(
      mongo_obs_without_prefix,
  ):
      print("without_prefix_test")
      runs_collection = mongo_obs_without_prefix.runs
      metrics_collection = mongo_obs_without_prefix.metrics
      assert runs_collection.name == "runs"
      assert metrics_collection.name == "metrics"
  
imports: import datetime
  import os
  import sys
  from glob import glob
  import mock
  import pytest
  from sacred.metrics_logger import ScalarMetricLogEntry, linearize_metrics
  import gridfs
  from mongomock.gridfs import enable_gridfs_integration
  from .failing_mongo_mock import FailingMongoClient
  from sacred.dependencies import get_digest
  from sacred.observers.mongo import MongoObserver, force_bson_encodeable
label_desc: Use image node_id 29 for calling a global function with example usage: test_mongo_observer_created_without_prefix(mongo_obs_without_prefix) without return types