Image-classification-transfer-learning.ipynb failed CI

Link to the notebook:
https://github.com/aws/amazon-sagemaker-examples/blob/master/introduction_to_amazon_algorithms/imageclassification_caltech/Image-classification-transfer-learning.ipynb

Error:

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Exception encountered at "In [2]":
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ParamValidationError Traceback (most recent call last)
in
23
24 download('http://data.mxnet.io/data/caltech-256/caltech-256-60-train.rec')
---> 25 upload_to_s3(s3_train_key, 'caltech-256-60-train.rec')
26 download('http://data.mxnet.io/data/caltech-256/caltech-256-60-val.rec')
27 upload_to_s3(s3_validation_key, 'caltech-256-60-val.rec')

in upload_to_s3(channel, file)
13 data =

[...]

Invalid bucket name "<>": Bucket name must match the regex "^[a-zA-Z0-9.\-_]{1,255}$" or be an ARN matching the regex "^arn:(aws).*:s3:[a-z\-0-9]+:[0-9]{12}:accesspoint[/:][a-zA-Z0-9\-]{1,63}$|^arn:(aws).*:s3-outposts:[a-z\-0-9]+:[0-9]{12}:outpost[/:][a-zA-Z0-9\-]{1,63}[/:]accesspoint[/:][a-zA-Z0-9\-]{1,63}$"

Open the linked Image-classification-transfer-learning.ipynb and inspect cell In [2], especially upload_to_s3 and the S3 bucket value used before the failing upload. Reproduce the CI failure, determine why the bucket value is invalid, and confirm that the notebook completes its checks with a valid configuration.

Written by the indexing model from the issue text.