code: def test_default_bucket_exists(sagemaker_session):
      sagemaker_session.boto_session.resource(
          "s3"
      ).meta.client.head_bucket.return_value = {
          "ResponseMetadata": {
              "RequestId": "xxx",
              "HTTPStatusCode": 200,
              "RetryAttempts": 0,
          }
      }
  
      bucket_name = sagemaker_session.default_bucket()
      assert bucket_name == DEFAULT_BUCKET_NAME
  
file_path: sagemaker-python-sdk/tests/unit/test_default_bucket.py
imports: from __future__ import absolute_import
  import datetime
  import pytest
  from botocore.exceptions import ClientError
  from mock import MagicMock
  import sagemaker
label_desc: Use image node_id 8 for calling a global function with example usage: test_default_bucket_exists(sagemaker_session) without return types