def clear(self):
        "Remove all rows and reset internal structures"
        ## list has no clear ... remove items in reverse order
        for i in range(len(self)-1, -1, -1):
            del self[i]
        self._key = 0
        if hasattr(self._grid_view, "wx_obj"):
            self._grid_view.wx_obj.ClearGrid()
Remove all rows and reset internal structures