Library.getRemoteLibraryWithRSS() errors

cc8476

when i follow the js api about Library, an error occurs like this

MOJavaScriptException: TypeError: o.remoteLibraryWithAppcast is not a function. (In 'o.remoteLibraryWithAppcast(n)', 'o.remoteLibraryWithAppcast' is undefined)
picasso.addlib

and here is my code

var Library = require('sketch/dom').Library
Library.getRemoteLibraryWithRSS(
  'https://url/to/feed/rss.xml',
  (err, library) => {
    if (err) {
      // oh no, failed to load the library
    }
  }
)