code: def _key_exists(bucket_name, key):
      s3 = boto3.resource("s3")
      try:
          s3.Object(bucket_name, key).load()
      except ClientError as e:
          if e.response["Error"]["Code"] == "404":
              return False
      return True
  
imports: import datetime
  import pytest
  import json
  import os
  from sacred.observers import S3Observer
label_desc: Use image node_id 5 for calling a global function with example usage: _key_exists(bucket_name, key) and returns: True, False