code: public void removeCollaborator(String appName, String collaborator) {
          connection.execute(new SharingRemove(appName, collaborator), apiKey);
      }
docs: Remove a collaborator from an app.
  @param appName App name. See {@link #listApps} for a list of apps that can be used.
  @param collaborator See {@link #listCollaborators} for collaborators that can be removed from the app.