Invalid JSB_CHORALES download https link

[sejabs]

• What tutorial are you running?
  numpyro dmm-steinVI
• What version of Pyro are you using?
  numpyro 0.17
• Please link or paste relevant code, and steps to reproduce.
  Downloading: https://d2hg8soec8ck9v.cloudfront.net/datasets/polyphonic/jsb_chorales.pickle
  HTTPError

It seems the cloudfront service is down.

[fehiepsi]

Thanks for the report! We will address the issue soon. (in the future, please use github issues to report the bugs)