Update by applying CLA Assistant

[oss-kakao]

Thanks for your contribution :) Before you submit this pull request, please ensure it is against the dev branch and not master.

• [x] ensure branch where you submitting, it should be dev.
• [x] check your coding convention.
  • 4 spaces for indentation
  • pep8 for Python

remove above message before submitting your pull request.

[CLAassistant]

All committers have signed the CLA.