How to programatically change active cell?

Hello, on certain events in a notebook, I’d like to progamatically change the active cell in my extension, as if the user pressed esc and then clicked on a cell. Is there any way to do this? INotebookTracker.currentWidget.content.select() seems close visually, but does not change the active cell.

Set the activeCellIndex: INotebookTracker.currentWidget.content.activeCellIndex = 3, for example.