## Description
<!-- Brief description. Refer to the related issues if existed.
It'll be great if relevant reviewers can be assigned as well.-->

## Checklist
Please feel free to remove inapplicable items for your PR.
- [ ] The PR title starts with [$CATEGORY] (such as [NN], [Model], [Doc], [Feature]])
- [ ] Changes are complete (i.e. I finished coding on this PR)
- [ ] All changes have test coverage
- [ ] Code is well-documented
- [ ] To the my best knowledge, examples are either not affected by this change,
      or have been fixed to be compatible with this change
- [ ] Related issue is referred in this PR
- [ ] If the PR is for a new model/paper, I've updated the example index [here](../examples/README.md).

## Changes
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- [ ] Feature1, tests, (and when applicable, API doc)
- [ ] Feature2, tests, (and when applicable, API doc)
-->
