rl_network_compression_ray_custom.ipynb failed CI

Link to the notebook:
https://github.com/aws/amazon-sagemaker-examples/blob/master/reinforcement_learning/rl_network_compression_ray_custom/rl_network_compression_ray_custom.ipynb

Error:

---------------------------------------------------------------------------
Exception encountered at "In [10]":
---------------------------------------------------------------------------
NotADirectoryError Traceback (most recent call last)
in
----> 1 estimator.fit(cifar_inputs)

/usr/local/lib/python3.7/site-packages/sagemaker/estimator.py in fit(self, inputs, wait, logs, job_name, experiment_config)
665
666 """
--> 667 self._prepare_for_training(job_name=job_name)
668
669 self.latest_training_job = _TrainingJob.start_new(self, inputs, experiment_config)

/usr/local/lib/python3.7/site-packages/sagemaker/estimator.py in _prepare_for_training(self, job_name)
2200 self.code_uri = self.uploaded_code.s3_prefix
2201 else:
-> 2202 self.uploaded_code = self._stage_user_code_in_s3()
2203

[...]

NotADirectoryError: [Errno 20] Not a directory: 'common/sagemaker_rl'