code: def exists(self, object_name):
      bucket = self.client.bucket(self.bucket)
      blob = bucket.blob(object_name)
      return blob.exists()
  
imports: import os
  from typing import Dict, Optional, Union
  import pydantic
  from google.api_core.exceptions import GoogleAPIError, NotFound
  from google.cloud import storage
  from google.cloud.storage import Client
  from structlog import get_logger
  from tenacity import retry
  from modelkit.assets import errors
  from modelkit.assets.drivers.abc import StorageDriver, StorageDriverSettings
  from modelkit.assets.drivers.retry import retry_policy
label_desc: Use image node_id 7 for calling the GCSStorageDriver obj's underlying member method code with example usage: obj.exists(object_name) and returns: blob