def METHOD_NAME(self, event):
    range_selection_event = event.new
    # The event obj should be a tuple (low, high) in data space
    if range_selection_event is not None:
        low, high = range_selection_event
        self.price_plot.index_range.low = low
        self.price_plot.index_range.high = high
    else:
        self.price_plot.index_range.set_bounds("auto", "auto")