<!--- Thank you for submitting a Pull Request! In order to make our work smoother. -->
<!--- please make sure your Pull Request meets the following requirements: -->
<!---   1. Provide a general summary of your changes in the Title above; -->
<!---   2. Add appropriate prefixes to titles, such as `build:`, `chore:`, `ci:`, `docs:`, `feat:`, `fix:`, `perf:`, `refactor:`, `revert:`, `style:`, `test:`(Ref: https://www.conventionalcommits.org/). -->
<!--- Category: -->
<!--- Patch Updates: `fix:` -->
<!---   Example: fix(auth): correct login validation issue -->
<!--- minor update (introduces new functionality): `feat` -->
<!---   Example: feature(parser): add ability to parse arrays -->
<!--- major update(destructive update): Include BREAKING CHANGE in the commit message footer, or add `! ` in the commit footer to indicate that there is a destructive update. -->
<!---   Example: feat(auth)! : remove support for old authentication method -->
<!--- Other updates: `build:`, `chore:`, `ci:`, `docs:`, `perf:`, `refactor:`, `revert:`, `style:`, `test:`. -->

<!--- Provide a general summary of your changes in the Title above -->

## Description
<!--- Describe your changes in detail -->

## Motivation and Context
<!--- Are there any related issues? If so, please put the link here. -->
<!--- Why is this change required? What problem does it solve? -->

## How Has This Been Tested?
<!---  Put an `x` in all the boxes that apply: --->
- [ ] Pass the test by running: `pytest qlib/tests/test_all_pipeline.py` under upper directory of `qlib`.
- [ ] If you are adding a new feature, test on your own test scripts.

<!--- **ATTENTION**: If you are adding a new feature, please make sure your codes are **correctly tested**. If our test scripts do not cover your cases, please provide your own test scripts under the `tests` folder and test them. More information about test scripts can be found [here](https://docs.python.org/3/library/unittest.html#basic-example), or you could refer to those we provide under the `tests` folder. -->

## Screenshots of Test Results (if appropriate):
1. Pipeline test:
2. Your own tests:

## Types of changes
<!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
- [ ] Fix bugs
- [ ] Add new feature
- [ ] Update documentation
