Gtk.ListStore.prototype.insert

function insert(position:Number):void {
    // Gjs wrapper for gtk_list_store_insert()
}

Creates a new row at position. iter will be changed to point to this new row. If position is -1 or is larger than the number of rows on the list, then the new row will be appended to the list. The row will be empty after this function is called. To fill in values, you need to call Gtk.set or Gtk.set_value.