yzhao062/Pyod

### All Submissions Basics:

* [ ] Have you followed the guidelines in our Contributing document?
* [ ] Have you checked to ensure there aren't other open [Pull Requests](../../pulls) for the same update/change?
* [ ] Have you checked all [Issues](../../issues) to tie the PR to a specific one?

### All Submissions Cores:

* [ ] Have you added an explanation of what your changes do and why you'd like us to include them?
* [ ] Have you written new tests for your core changes, as applicable?
* [ ] Have you successfully ran tests with your changes locally?
* [ ] Does your submission pass tests, including CircleCI, Travis CI, and AppVeyor?
* [ ] Does your submission have appropriate code coverage? The cutoff threshold is 95% by Coversall.

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### New Model Submissions:

* [ ] Have you created a <NewModel>.py in ~/pyod/models/?
* [ ] Have you created a <NewModel>_example.py in ~/examples/?
* [ ] Have you created a test_<NewModel>.py in ~/pyod/test/?
* [ ] Have you lint your code locally prior to submission?