I posted a posting on my company blog before
https://medium.com/smartstudy-tech/pinkfong-membership-sdk-%EA%B0%9C%EB%B0%9C-%ED%94%84%EB%A1%9C%EC%84%B8%EC%8A%A4-%EB%A7%8C%EB%93%A4%EA%B8%B0-9401e84b36b3