[PowerPoint javascript API] Add or remove slide master

When create a new Presentation, it always adopts existed or default slide master, there is no solution to create a new slide master or remove not used slide masters.

Would it be possible to add interfaces to add/remove SlideMaster objects?

1. use case 1, As a presentation creator, I would like to create/copy a new slide master and assign it to specific slides
2. use case 2, As a presentation editor, I would like to remove not used slide master to reduce file size