code: def _bucket_exists(self):
      from botocore.errorfactory import ClientError
  
      try:
          self.s3.meta.client.head_bucket(Bucket=self.bucket)
      except ClientError as er:
          if er.response["Error"]["Code"] == "404":
              return False
      return True
  
imports: import json
  import os
  import os.path
  from sacred.commandline_options import cli_option
  from sacred.dependencies import get_digest
  from sacred.observers.base import RunObserver
  from sacred.serializer import flatten
  import re
  import socket
label_desc: Use image node_id 3 for calling the S3Observer obj's underlying member method code with example usage: obj._bucket_exists() and returns: True, False