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## Motivation

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## Modification

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## BC-breaking (Optional)

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## Use cases (Optional)

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## Checklist

**Before PR**:

- [ ] I have read and followed the workflow indicated in the [CONTRIBUTING.md](https://github.com/open-mmlab/mmpose/blob/master/.github/CONTRIBUTING.md) to create this PR.
- [ ] Pre-commit or linting tools indicated in [CONTRIBUTING.md](https://github.com/open-mmlab/mmpose/blob/master/.github/CONTRIBUTING.md) are used to fix the potential lint issues.
- [ ] Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
- [ ] New functionalities are covered by complete unit tests. If not, please add more unit tests to ensure correctness.
- [ ] The documentation has been modified accordingly, including docstring or example tutorials.

**After PR**:

- [ ] CLA has been signed and all committers have signed the CLA in this PR.