automate_model_retraining_workflow.ipynb failed CI

Link to the notebook:
https://github.com/aws/amazon-sagemaker-examples/blob/master/step-functions-data-science-sdk/automate_model_retraining_workflow/automate_model_retraining_workflow.ipynb

Error:

---------------------------------------------------------------------------
Exception encountered at "In [8]":
---------------------------------------------------------------------------
InvalidInputException Traceback (most recent call last)
in
22 WorkerType='Standard',
23 NumberOfWorkers=2,
---> 24 Timeout=60
25 )

/opt/conda/lib/python3.7/site-packages/botocore/client.py in _api_call(self, *args, **kwargs)
355 "%s() only accepts keyword arguments." % py_operation_name)
356 # The "self" in this scope is referring to the BaseClient.
--> 357 return self._make_api_call(operation_name, kwargs)
358
359 _api_call.__name__ = str(py_operation_name)

/opt/conda/lib/python3.7/site-packages/botocore/client.py in _make_ap

[...]

InvalidInputException: An error occurred (InvalidInputException) when calling the CreateJob operation: Role should not be null or empty.