                     self.presentError(title: "cannot fetch repositories", error: error)
                 }
             }
-        observer.send(value: cursor)
+        pagingObserver?.send(value: cursor)
     }
 
     // MARK: - ScrollVeiw
     override func scrollViewDidScroll(_ scrollView: UIScrollView) {
         if tableView.contentOffset.y >= (tableView.contentSize.height - tableView.bounds.size.height) {
-            observer.send(value: cursor)
+            pagingObserver?.send(value: cursor)
         }
     }
 

            return
        }

        signal
            .skipRepeats { $0 == $1 }
            .flatMap(FlattenStrategy.concat) { cursor in

    private let indicator: UIActivityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .gray)
    private var repositories: [RepositoryObject] = []
    private var cursor: FetchRepositories.Cursor?
    private var pagingObserver: PagingSignal.Observer?

    init() {
        super.init(nibName: nil, bundle: nil)
        self.title = "Add repository"
    }
