machine_learning_workflow_abalone.ipynb failed CI

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

Error:

---------------------------------------------------------------------------
Exception encountered at "In [16]":
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InvalidArn Traceback (most recent call last)
in
----> 1 workflow.create()

/opt/conda/lib/python3.7/site-packages/stepfunctions/workflow/stepfunctions.py in create(self)
203
204 try:
--> 205 self.state_machine_arn = self._create()
206 except self.client.exceptions.StateMachineAlreadyExists as e:
207 self.state_machine_arn = self._extract_state_machine_arn(e)

/opt/conda/lib/python3.7/site-packages/stepfunctions/workflow/stepfunctions.py in _create(self)
215 definition=self.definition.to_json(pretty=self.format_json),
216 roleArn

[...]

InvalidArn: An error occurred (InvalidArn) when calling the CreateStateMachine operation: Invalid Role Arn: ''

Open machine_learning_workflow_abalone/machine_learning_workflow_abalone.ipynb and inspect In [16], where workflow.create() fails. Reproduce the notebook run and trace how the execution role reaches the CreateStateMachine call. Done means the notebook no longer fails with Invalid Role Arn during workflow creation.

Written by the indexing model from the issue text.