code: def test_jumpstart_default_serializers(
      patched_get_model_specs,
      patched_verify_model_region_and_return_specs,
  ):
      patched_verify_model_region_and_return_specs.side_effect = (
          verify_model_region_and_return_specs
      )
      patched_get_model_specs.side_effect = get_special_model_spec
  
      model_id, model_version = "predictor-specs-model", "*"
      region = "us-west-2"
      mock_client = boto3.client("s3")
      mock_session = Mock(s3_client=mock_client)
  
      default_serializer = serializers.retrieve_default(
          region=region,
          model_id=model_id,
          model_version=model_version,
          sagemaker_session=mock_session,
      )
      assert isinstance(
          default_serializer, base_serializers.IdentitySerializer
      )
  
      patched_get_model_specs.assert_called_once_with(
          region=region,
          model_id=model_id,
          version=model_version,
          s3_client=mock_client,
      )
  
      patched_get_model_specs.reset_mock()
  
file_path: sagemaker-python-sdk/tests/unit/sagemaker/serializers/jumpstart/test_serializers.py
imports: from __future__ import absolute_import
  from unittest.mock import Mock
  import boto3
  from mock.mock import patch
  from sagemaker import base_serializers, serializers
  from sagemaker.jumpstart.utils import verify_model_region_and_return_specs
  from tests.unit.sagemaker.jumpstart.utils import get_special_model_spec
label_desc: Use image node_id 1 for calling a global function with example usage: test_jumpstart_default_serializers(patched_get_model_specs, patched_verify_model_region_and_return_specs) without return types