code: public BoxRequestsBookmark.AddBookmarkToCollection getAddToCollectionRequest(String bookmarkId, String collectionId) {
          BoxRequestsBookmark.AddBookmarkToCollection request = new BoxRequestsBookmark.AddBookmarkToCollection(bookmarkId, collectionId, getBookmarkInfoUrl(bookmarkId), mSession);
          return request;
      }
docs: Gets a request that adds a bookmark to a collection
  
  @param bookmarkId        id of bookmark to add to collection
  @param collectionId    id of collection to add the bookmark to
  @return      request to add a bookmark to a collection